It seems like most people fundamentally misunderstand the UN. The UN does not have a real army and they dont have any real control over member nations. The UN is all talk.
And talk is good. Talk is diplomacy. Talk is putting pressure on those who are doing wrong.
Maybe the UN is decades late on this subject? I’m not sure if they have addressed it in the past. But either way, publically calling out the atrocious American prison system is a good thing.