Darius, King of Persia, c500BC, was reported to have asked the Greeks at his court if they would eat the bodies of their ancestors, as the Callatiaens did. They were aghast. He then asked the Callatiaens if they would burn their ancestors, as was the custom in Greece. They were horrified.
Thus he showed there is no wrong or right answer. The poet Pindar wrote "Custom is king of all".
"One man's meat is another's poison" is the core of relativism. Like Darius, two and a half thousand years ago, our system of government must integrate the perspectives of millions of very different people in a widely multi-cultural society. Back then, the king held the power and his word became law. Today, the power rests with Parliament. It could just as well reside with the majority of constituents, using Interactive Democracy and widespread debate to integrate all their perspectives into a national view.