The most famous forms of Holocaust denial and revisionism tend to focus on Jews, casting doubt, for example, on how many were exterminated in the camps. But denying the impact the Nazis had on the other groups they targeted, including queer and trans people, disabled people and Romani people, is still Holocaust denial. Maybe someone should tell J.K. Rowling.
The vast majority of people dont know this. Its an obscure fact that people share regularly in forums like Lemmy, but are not part of any mainstream discussion of the holocaust.