It’s the premature transhumanist idea that “whether you are an doesn’t matter”. A world without racism would be nice. But we live in a world with racism. Therefore pretending race doesn’t matter exacerbates racial inequity and brings us further away from actually bringing about a transhumanist utopia.
To be charitable, in many types of human conversation, statements that sound like mere descriptions of people or society (“this is not who we are as a nation”, “adults don’t act like children”, “in life, friends are more important than money”) are frequently shorthand for normative ones (“I think our nation shouldn’t act that way”, “I think adults shouldn’t act the way I perceive is childish”, “people should value friendship in their lives much beyond mere economic transaction”), to the point where even people with the best of intentions don’t realize they’re conflating the usages. I think rationalists generally try to avoid this but even so it’s still possible to slip up and intend a normative statement when you use a descriptive one.
I would distinguish between someone saying “x doesn’t matter” as a sincere belief that “x shouldn’t matter” vs. “x doesn’t matter” as a cop-out or denial, even cover-up of situations where x mattering is unsavory to them and they wish to pretend things are hunky-dory.
I feel like the latter tarnished the reputation of the former.
I don’t know if this is the best analogy, but thinking on the fly, I can imagine someone saying “your personal happiness is more important than what people think” to justify being a jerk (after all, who cares what others think if I do something to piss them off) or “material things in life are overrated, the best things in life are free” as justification to not help the poor or solve inequality (after all, material things won’t make them happier, look the poor can learn to be satisfied living with what they have already have) all the while benefitting from material prosperity itself. That doesn’t mean the principles themselves don’t have any (or some reasonable) amount of goodness, even if people use them for nasty justifications.
I don’t have any stats on this, but while I wouldn’t be surprised that groups considered the default say this (e.g. white, western males in the west), this seems less asymmetrical in principle in some other situations (e.g. I could see in principle a non-western non-white person being the majority in their majority non-western non-white country saying something similar if they’ve only lived with people of one so-called “race”, under popular definitions, in their life).
When you mentioned “uninformed things about non-white non-Western ciswomen”, my imagination ran towards a group of homogenous (white, western male) people who sit around and bring up “hey, I heard group X (of non-white, non-western, ciswomen) have these (insert imagined bizarre rituals and habits), I heard from (source)” “Yeah, I heard that too (from other source)”, “My mom told me (insert same stereotype) is true when I was 5” or something.
Then, a newcomer (or two, or three or a bunch) from group X joins in the conversation and say “no, I (or we all) have firsthand knowledge of growing up in X society, and that is totally unlike what you described. There is no bizarre ritual like that, or perhaps it’s a garbled description of something real that’s exaggerated.” Had the newcomers not joined, the old-timers would not have been able to shed their misconception and update their knowledge (in the charitable case that it was a genuine example of misinformation and not malicious hatred of outgroup, though with conflict theory that’s always possible still).