It's actually not arbitrary at all. The UN came out of the league of nations, which was specifically a bunch of colonial powers and their offspring / colonies.

It's actually not arbitrary at all. The UN came out of the league of nations, which was specifically a bunch of colonial powers and their offspring / colonies. That is precisely the reason why some highly controversial UN resolutions were passed right after the second world war. It's almost ironic that China now wields so much more power over the path the UN is taking than the old colonial powers. But whenever people say this or that is a human right, we ought to remember that a lot of the things that are legally defined as human rights were at some point defined by some old colonial overlord until it wasn't. The founders of the UN definitely didn't think that people of any colour were the same or that interracial marriage is a human right.