The whole argument about which country is/has been the most oppressive out of all is based on a very important underlying argument - which nation/country/civilization has the right to criticize other countries?
It isn't. I'm not even sure the point
was to point out which had been the "most oppressive". Even if everyone involved is equally oppressive, that does not magically make anyone involved
not oppressive. It just makes them all equally assholes. Even if there
is a hierarchy of oppression, that does not exempt whoever's at the bottom from having been an oppressive jackass (at least at some point in the past) just because they were the
least oppressive of jackasses.
As for that western superiority nonsense... the only people, western or otherwise, that proclaim western superiority are idiots or pushing some kind of agenda. Much of the actual population is well bloody aware of how terrible their leaders are and that their country has done or is doing terrible things (if not necessarily the
extent.). Those that aren't are either blatantly ignorant (especially in this day and age, at least in the areas relatively open internet is a thing), willfully in denial, or actively obfuscating. Very few nations, if any, are free from atrocity. Current or otherwise.
As for who has the right to criticize wrong action -- the answer to that is
anyone. Because it's wrong action. Being a person that has also committed wrong action does not mean you lose the right to criticize the wrong actions of others. It just makes you either a hypocrite or repentant. Being fair, folks operating at the level of geopolitics
are usually the former. It
is true that there's definitely a certain sort of audacity involved with someone like Putin (as an example) calling people out (because it's pretty likely they're going to turn around and do the same thing), but if he's calling out other people with good reason, well... that wouldn't change the facts of the issue he's criticizing. At most, it'd just mean he's trying to milk the issue for publicity of some sort, which is a thing
entirely separate from whatever issue is being criticized.