I don't know why I am bothering to quarrel with the Pope, because this is the Pope we are talking about here, and who bothers with the Pope these days, right? However since the Pope wants to quarrel I thought I would reciprocate.
Now according to the Pope's latest bad tempered sounding venting, moral values must be imposed upon the majority by the religious minority, for the will of the majority can be wrong in a democracy, and so therefore the duty of imposing moral values on the rest of the society falls upon religious people. Since there are very few Catholics left, and certainly not enough Catholics left to impose Catholic morality upon an uninterested and unwilling population, the Pope has appealed to the Muslims and yes, even all the Protestants he can get on board, since before that plan could ever work he would need as big a minority as he can get if he is to have even a slim distant hope of imposing religion upon the unwilling and uninterested majority.
The Pope saw fit to emphasize the rationality of what he refers to as 'Natural law' which stands in opposition to what he refers to as 'ethical relativism'. According to the Pope, there are "primary and essential norms that regulate moral life...In its main precepts Natural Law is presented in the Ten Commandments ... because the reason that proclaims it is a characteristic of human nature...the doctrine of natural moral law clashes with other concepts which run directly contrary to it...majorities can make mistakes. True rationality is not guaranteed by the consensus of the greater number...scepticism and ethical relativism managed to annul the fundamental principles of natural moral law...the consciences of all men and women of good will must be mobilized, both lay people and followers of religions other than Christianity, so that together they may make an effective commitment to creating...the conditions necessary for a full awareness of the inalienable value of natural moral law."
According to the Pope we know that the Ten Commandments are not just some rules cooked up by ancient priests, but are in fact the divine revelation of a god type being, because reason proclaims this to be true. He also points out that natural law clashes with other concepts that stand in opposition to it, and since the majority are clearly wrong it is the duty of the minority of religious people to all join together in one mob to do something about it. Just what that might be, I do not know, unless he is referring to fascism, which is about the only way that a minority could ever employ the force required to overturn democracy, which the Pope doesn't like to much, and force religion on everyone else.
And it is the forcing of religion on everyone else that we are talking about here, and for that reason we must address the issue of whether or not such a religion has any merit so that it might lay claim to encapsulating the Natural Law.
We know that the Bible is a contradictory hodge podge, and reason proclaims this to be true. For example, in one of my favorite contradictory passages, Jeremiah proclaims the law of the Bible to be forgeries created by the priests of the day. In the seventh chapter he condemns the document of Leviticus and its animal sacrifice rituals, as well as the abominable practice of burning people at the stake for violations of religious sex laws, stating 'that was no command of God's.' In the eight chapter he complains that because of these Bible laws 'my people no longer understand the requirements of God. How can you say, 'we are wise, for we have the laws of God, when actually the lying pen of your priests have made it into a lie.' We are left to decide whether Leviticus and its story of Moses going up the mountain to bring down the priestly laws, including the Ten Commandments, is true or whether the condemnation of the priest for forgery found in the Jeremiah is true. Reason tells us that the prophet is the one making sense here, for as the argument from reason is made is the 50th Psalm by another critic of those priests and their forged laws, 'God does not need any sacrificed animals, for all the animals in the world belong to God.'
We also know that Moses did not just bring down those Ten Commandments from that mountain (since apparently it was the plan the whole time for Moses to release those slaves from bondage to Pharoah only to enslave them to priests, a sad ending to that story of liberation). Apparently Moses also brought down such gems as the following : 'When a man beats a slave to death he is not to be punished for the slave is his property.' Apparently it was alright to be the slave driver, but being the slave yourself was unacceptable. Or, 'if a man has sex with a slave girl, he is not to be punished. She is a slave.' Or, 'When you see a beautiful woman and find her desirable, then you may take her...if she ceases to please you then send her away.' Now it is hard to imagine any religious person arguing in favor of these laws, which then leads one to wonder why we would show favoritism and just pick out some law and then claim that it was of divine origin when reason tells us that what we have here are six hundred or so worthless laws that were obviously forged by the priests at that time. Now someone might suggest that we just pick out Ten of those laws that we like, but once again we are confronted with the problem of the source, which is the Bible, a notoriously fucked up and ruined book, and reason tells us that we have good reason to doubt the value of just about anything that comes from such a book, and can take nothing for granted given what a totally screwed up contradictory mess we have here. Reason also tells us that all people are human and thus pretty much made of the same stuff, and so therefore some fabricated argument that a Pope is someone special is an insult to reason, for it is quite likely that a Pope wipes his ass after using the toilet, and is pretty much the same as anyone else in everyway that really counts.
We also know that Yeshua ('Jesus') broke the Ten Commandments all the time, in particular that one about 'keeping the Sabbath', something he never bothered to do. In fact, it would appear that he went out of his way to work on the Sabbath, harvest on the Sabbath, or so we are told, and if we ignore the brainless excuses cooked up by the religious right in an attempt to make it seem like he had a perfectly valid reason each time he did that, thus proving that he wasn't really breaking the Ten Commandments, it becomes obvious that he was indeed making a statement by breaking those Ten Commandments, since it was not required that he do so and therefore he could only have been doing so by choice because he always had the choice of not pissing off the Pharisees on purpose. As those Pharisees always reminded him, quoting the Ten Commandments, 'six days you have to do your work but not on the Sabbath.' Apparently it is characteristic of a true Pharisee to feel the need to remind people of the obvious, and it was characteristic of Yeshua to antagonize religious people on purpose by inviting such condemnation for breaking the Ten Commandments.
We know that the Bible is a contradictory hodge podge, and reason proclaims this to be true, and here we have just one more of those contradictions in the Bible, only more radical than what you find in a prophet, and we also have an interesting contradiction between Yeshua and the Pope. This would not be the only one. For example, we are told that Yeshua said, 'you must not call me good, for only God is good.' This conflicts with the doctrines of Popes who taught that this Jesus of theirs was sinless, and very, very good, and in fact was a god. He also taught the people that you must not recognize any human claim to be an authority for everyone is equal and only God is the legitimate authority. "Do not call anyone on earth 'father'." We must assume then, that according to this Jesus of yours, no one earth must ever call some Pope 'Holy Father', not that this ever stopped a Catholic, for as we know Catholics are brazen hypocrites, and even when you confront them with something like that they just keep right on doing it. At the same time they claim to be the veritable mouth piece of God and this Jesus they carry on about. Reason tells us that these sorts of naked hypocrites are not the type we want ruling over the majority or presuming to impose any sort of morality upon the rest of us, since apparently they have none themselves and are in fact hypocrites.
We know that the source of Natural Law could never be the fucked up Bible. Religious people agree with me on this point, for as I mentioned, you can try that stunt of teaching a Catholic, for example, the Bible, and it makes no difference to them, and so therefore I cannot see why it should make any difference to anyone else. Even Catholics do not consider that screwed up ruined book, the Bible, to be some kind of authority in matters of doctrine, which becomes very obvious when a person attempts to teach simple Bible doctrines to a Catholic only to be told to go to hell.
If we can all agree that the Bible is not the source of moral values or Natural Law, then it must follow that the source for Natural Law must be found in the Natural World. This makes perfect sense, for it would be impossible for a priest to fuck up the Natural World and so we would suppose that at least here, in the natural world, we could expect to find unsullied and perfect natural law.
In the past I have made note of the conflict that exists between Canon Law and Natural Law, with Canon Law clearly promulgating easily refuted falsehoods concerning the observable reality of the natural world. Now let us consider one more example of where religious canon law conflicts with observable Natural Law, for as you yourself said, "the doctrine of natural moral law clashes with other concepts which run directly contrary to it." Where such a conflict is found to occur we would then know that the source of conflict was a falsehood masquerading as a Natural Law, for it was actually found to be in conflict with the Natural Law and thus ran directly contrary to it. This sort of observation should be all that is required to judge any system of thought which lays claim to giving expression to 'Natural Law'.
We know that it is the commandment of Natural Law that at around the age of 12 or 13 human beings go through puberty at which time, according to observable Natural Law, it is then required of them that they become sexually active. This age, around 12 or 13 must therefore be the right age for sexual activity, and since Natural Law can only be the Law of God, since we assume that devils don't create worlds, therefore this is also the plan of God for human adolescents. That this is abundantly true is proven by the surging rush of hormones that begins pumping through the veins of our teenagers, and in human males, they reach the very peak of their sexual vigor, with the highest amount of these hormones, sometime around the age of 18, with the amount of these sexual hormones and their sexual drive steadily increasing throughout adolescence as the gas pedal is pressed right to the metal. This is why religious people are required to participate in these hysterical and ridiculous looking abstinent chastity drives, for religious people are fighting a full scale war against God, for God is pressing the gas pedal while religious hysterics, who see that the gas pedal is clearly being pushed to the floor, frantically try to apply the brakes.
This is one fine example of how you people nullify the Law of God for the sake of your own cultural and religious traditions and you do many other things just like that.