This is not surprising, this is how society ultimately works, even internally, not just on international scale.
I live in a democracy. I could still name several laws of the land that I consider fundamentally unjust, but the might of the majority translated into political and physical power means that I have to obey them, right or wrong. It is better that this power is controlled democratically and not by a single autocrat or a single ruling party, but it is still fundamentally coercion.
Are there even any alternatives? Ultimately we cannot all agree on what is right for everyone.