Some people really struggle with the idea that an antiracist argument or analysis can be wrong. Not because racism is good and right, but because the argument is poorly made or contains factual errors that undercut or undo the conclusion (or even framing).
And I struggle with how to communicate this without my natural inclination to turn every point into a 2-gin-drinks-into-the-evening zinger. Talking about racism is hard. Important hard. Maybe I'll get better at it someday...
Well, I think that there are different things going on here.
On the one hand, you have communities and the people within them, often with a history of being marginalized by the dominant power structures. One way to marginalize valid concerns is to employ various techniques, such as sealioning, or ignoring the "bigger picture" to concentrate on small issues or the form of the protest, or just tone policing (Why so angry?). All of this has a long history, and it is so frustrating to have valid concerns dismissed by people that have no actual interest in addressing the substance of what you're saying; in effect, it's dismissive.
The flip side of that, of course, is that while people have personal experiences that are valid for them ... if you are making a generally applicable critique of something, if you are trying to persuade people, then you have to actually get your facts correct. And when these issues arise, far too often people resort to variations of, "Well, that's just tone policing / gatekeeping whatever." Or, "You can't comment unless you are the specific marginalized community- and even if you are, you have to have a appropriate opinion or you are the equivalent of Clarence Thomas / Milo Yiannopoulos ...." Or, "You need to listen, and not talk." All of this can be incredibly frustrating to people when they have valid concerns about an analysis and how it affects the substance; in effect, it's dismissive.
And I think that this is frustrating for everyone. It can be very hard to tell the difference between someone who generally agrees with you and has good-faith issues with some specifics, as opposed to someone who is simply using argument in order to frustrate you and turn the issue into something else. Just like it can be frustrating when you see something that is clearly in error (here, comeliness, or the false etymology of picnic that was circulating for a while) and people just keep doubling down.