The UN at that time was a fairly new institution, and China’s seat was denied to it and given to Taiwan, leading to the USSR to boycott it. The UN that invaded Korea was mostly just the US and Western Europe, it doesn’t provide the moral cover you want it too.

Ideally, neither the US nor the USSR and China would have been involved. But if you’re justifying US imperialism by arguing that the USSR and China were being imperialistic, then I see no reason why their positions wouldn’t be justified on the same basis. It’s nonsense. Two wrongs don’t make a right.

Again, it’s a simple question, so go ahead and answer it. Who actually benefitted from the US bombing the hell out of Korea and deploying chemical and biological weapons on its people? And if no one benefitted, then why the hell do you support it?