They are very consistent, just duplicitous about it. You can easily notice that when it's about "colonizing powers", it's always exclusively about the western ones. No mention is ever made to ask for China, Mongolia, Turkey or Arabia to pay reparation or to take responsibilty for the vassalization of other countries.
so just to chime in here, and not to ignore the rest of the post (white guilt exists, etc etc). it's a behavior that seems weird, but there are three practical reasons for this often overlooked.
first off, there's the question of impact and relative strength. mongolia, turkey, and (the region of) arabia simply doesn't have the material and political capital the west at large has. they're all dwarfed. china is the odd one out of course and has tremendous influence, but more on that below.
second, there's the question of what you can actually control. you have more influence towards those that are part of your sphere than those that aren't. i'm not a chinese citizen, i'm a citizen of a nato country, so while i have very meagre influence where i live, it'd be much more absurd for me to push for changes in china.
and lastly, the basic reason other spheres aren't often brought up is that
it's not what we're talking about. often these discussions sprout out of domestic policy questions. when you talk america, the question of colonization is inevitably ingrained into the political environment of that nation, and you then look to the general behavior of us' colonizers when discussing this very behavior. we were discussing the english overlord behavior here at the onset of this thread. not chinese overlord.
basically, for the "duplicitous" leftie you're angy about, the question has to check three boxes; is the power relevant; is it within our sphere of action, often as in what we're actively doing already; and is it on topic. the reason the mongolian conquests aren't brought up is because they fail to check the three.
now, a longer tangent on this. is it abstractly useful to discuss colonization at large as it relates to eg britain, looking at chinese behaviors in africa today, arabian behaviors in the past (albeit that's kind of a different thing), the romans, etc? surely. that's why discussions on china are quite common internally among leftists. it's just often treated carefully when it comes to these things, because the vast majority of times non-western behavior is brought up, it's to soften western behavior. so lefties will not engage (or they will, to dismiss). eg discussing belgian colonization, some conservative shows up to yell what about china, they high five themselves and leaves. nothing is solved. and in spite of the name of this thread, the topic specifically had to do with a hiccup about the benevolence of
british imperialism. so lefties will not naturally bring up china (
why would they) and when china is brought up, every reading of the poster will basically make sure it gets a pass of being western whining and/or apologeia. because more often than not, it just is.
i have throngs of leftists i can criticize china with, but if i do it to make a whataboutism, they're right to clock me and laugh me out the door. that's a fair situation. bringing up china should be relevant for bringing up china, not to poison the discussion.
it's a very conservative worldview to be sad that you don't get to abuse minorities anymore, and lefties are very watchful on when china is brought up as abstractions on human behavior or apologeia to rein the colonies back in. it's always strange to see vaguely left-leaning people having lost the sauce here, and having fallen to these distractions, because while it's true that china did and does a lot of abuses, there's no reason to get baited by the rhetoric.
i have an acquaintance who is supposedly an artist. a quarter of their facebook feed were musings on artistry and philosophy (good musings, too). half of it was variations of WHY DOES THE LEFT NEVER BRING UP CHINA? the last quarter was stuff like heartfelt excitement over the novel notion of illiberal democracy. he really,
really liked the latter, he really hated the left, and he was in the enviable position where you couldn't tell whether he was stupid af or i-can't-believe-it's-not-dogwhistling-all-over-the-place. all of his friends knew what he wanted to
do politically, so there was no real use "discussing china" with him.
so it has to be colonization relevant to the discussion at hand; and from the tangent, it's also a space where you have to be really careful about what the purpose of the conversation is when discussing nonwestern countries. the duplicitousness is a complete nosequitor. considering the left manipulative is ridiculous. the stereotypical leftie is not one that does rhetorical tricks; it's one who's abrasive, can't pick a fight, can't shut up, and has no strategic filter as to the listener in question.