The fact that America wanted to allow Vietnam and Korea the same economic freedom that they have does not make this a black mark on their human rights record. If you ask me it improves it. Whereas China wanted them controlled by dictators with similar communist principles. In both cases, it was the north that attacked, not the south. So America defended, they did not attack, hence they were not the aggressors.
china didn't even fight in vietnam, they just supplied as far as i know. if i apply your logic concerning the u.s.-latinamerican relationship including the american tactics for decades down there, that means technically china hasn't done anything wrong whatsoever.
anyways, the thing is that america policed the world continuously during the last century and, as you know, they NEVER refrained from adopting illegal methods in order to get the job done - which obviously includes massive violations of human rights. they've been active all across the globe while china hasn't gone to any country they couldn't have reached by bike. sure, china didn't ask its people if they wanted to be free in the western sense. but has america asked those countries that suffered during american attacks if they actually believed in the values america forced upon them? both countries had certain ideologies and because both have been "in the zone" beyond belief they failed to stick to moral values in the first place.
this is going nowhere though. fact is: america has had its fair share of human rights violations. period.