Ethics are not subjective. People merely disagree on what the right ones are. There is some optimal set of ethics which, if consistently followed, will lead to

Ethics are not subjective. People merely disagree on what the right ones are. There is some optimal set of ethics which, if consistently followed, will lead to an optimal set of outcomes. We're not clever enough to figure them out, though, and so people will quite happily come up with their own, inevitably self-serving ethical systems in which "the things I want to do are right, the things you want to do are wrong". Getting everyone to behave perfectly ethically is impossible, but telling everyone that their own self-serving ethical systems are perfectly valid is one of the worst things you can do.