> What some consider 'oppression' today was the norm globally. The problem is moral realism/anti-realism, since you can't prove your moral value judgments with science they will remain subjective and thus naturally be opposed.

I'm afraid no amount of appeal to the evils of moral relativism are going to be enough to convince me that homosexuality is legal in most countries where the judgments of sharia courts are routinely enforced by the government.