Sometimes some man from a cannibal nation who does not want to kill people and eat them out of his nature might be a vegetarian which isn't about The Law.I agree that sometimes it is an act. Such as the love bombing and forever smiling. Some act nice in a Kingdom Hall and act very different at home. I think that all do that to a certain extent because who they really are they cannot suppress for long. Their true nature leaks out. But many are trying to better themselves.
Your second point I tend to not agree with. The law in the heart is naturally doing the right moral thing in certain cases. Being deceived doesn't fall under moral law. For instance, a man from a cannibal nation who does not want to kill people and eat them out of his nature has the law written in his heart.
I will have to reconsider something. I did not know that the law can be written on anyone's heart.
I thought that the law had to be learned first.