This is really a reflection of a particular viewpoint on moral values, ethical thinking. It's called normative ethical relativism. Big, fancy words. I'll give you my short form, my thumbnail version. In other words, it is a view about morality that holds that you ought to do what society tells you to do.
Every society has their own viewpoint.
Ours has its particular viewpoint and you are morally obliged to do what your society says. It's also called conventionalism. This conviction, it seems, is at the heart of those who say, come on, accept it. It's the law. End of issue.