Where someone attempts to invalidate anything that’s problematic to their narrative and/or would trigger cognitive dissonance. Conspiracy theorists do this a lot, but so do your garden-variety bigot: when you’re outed as a drug addict, anyone can literally accuse you of anything, because no matter what you say or how stupid the accusation is, “junkies will do or say anything for dope,” “well of course junkies lie,” and “maybe you don’t remember because you were tweaking hard.”
You don’t have to define it to be able to beat up the person who said it
/s
LangelyDominos said “poisoning the well” and while I kind of agree, I think the fallacy is just straight up bigotry. Poisoning the well is defined as “presenting bad things about a person to discredit their argument” when there is no facts presented in your case. It’s literally just “Don’t listen to this person, they’re an other!” Of course there’s more nuance, but the key thing is that there’s stereotypes about your group, and they’re appealing to those stereotypes rather than the factual realities of your oppression. /srs