The fallen man denies that he is the image of God. This is a major revelation of Natural Law and yet fallen man denies this testimony of Natural Law suppressing the truth in unrighteousness and insisting that he most certainly not God’s image bearer.
Now, if the fallen man get this most obvious of Natural Law truths wrong because of his suppression mechanism then how can Natural Law be the fallen man’s guide to life except inasmuch as Natural Law serves fallen man’s to climb up into God’s lap in order to slap God in the face.
Example – The sodomite might agree that Natural Law teaches marriage (climbing up in God’s lap) but only with the purpose of marrying his male consort (slapping God in the face).
So, it may be the case that fallen man will get natural law right from time to time but it always ends up being stolen capital in order to get his Christ denying worldview off the ground. No anti-Christ worldview can ever be perfectly anti-Christ consistent. If it were it could never last since all perfectly anti-Christ worldviews end up in the graveyard. As such all anti-Christ worldviews sneak Christian capital into them in order to be successful enough not to kill themselves.