Because it's immaterial to suggest the majority of the global north can just do something about it. It's almost religious in a way to do so, that they're evil inherently. It also denies the real suffering of the proletariat class and the lumpenproletariat too, something that will became ever more apparent in the coming future as the empire contracts. You're also blaming Proletarians for the conditions and relations laid upon them, which is something Lenin described the Bernsteinites of having the symptom of

the problem is that you are holding yourself to an idealist standard.

as i said in a previous comment, we should reject the leap from "i (marginally) benefit from an unjust system" to "i should hate myself, and people harmed by that system should condemn me as a person."

guilt isn't the same as accountability. feeling bad may acknowledge harm, but self-condemnation by itself leads to nothing good and only causes harm to yourself and the movement. a more useful question is: "what do i participate in, what power do i have, and what can i do with others to change it?" that points towards political solidarity and material change, rather than treating self-hatred as proof of moral seriousness.

"i'd condemn myself in their shoes" is projection, not evidence. it assumes people harmed by imperialism would all respond alike, and that your imagined reaction tells you what they actually think. people in the global south are not a single moral tribunal. some may (in my opinion wrongly) view you with dislike; others may be more intelligent and focus criticism on actual governments, companies, institutions, or particular actions. their views deserve to be heard as specific views, not guessed at or generalised.

don't make harmed people responsible for condemning or absolving you! listen to particular people and movements without expecting moral judgement or expecting one person to speak for everyone. take criticism seriously, but don't turn it into a verdict that you are irredeemably bad.

you are not guilty by birth or geography! you don’t need to hate yourself to oppose imperialism. you only need to understand your position, listen without expecting to be judged on moral grounds, and act with others against the structures causing harm.