I think there are few important keywords that could facilitate OP's research on this: - moral relativism and ethical subjectivism: https://en.m.wikipedia.org/w

I think there are few important keywords that could facilitate OP's research on this: - moral relativism and ethical subjectivism: https://en.m.wikipedia.org/wiki/Moral_relativism https://en.m.wikipedia.org/wiki/Moral_relativism - In-group vs. out-group