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.
I had a look at the homepage of the holocaust museum. They differentiate between soft and hard holocaust denial, i.e. the genocide of the Jews wasn’t planned and didn’t happen at this scale, and the the genocide of the Jews didn’t happen, respectively.
That is, by the way, in line with Wikipedia states. I don’t expect you to actually walk away and learn something of course, but on the off chance that you’ll reflect on this I’d say: start opening your mind to the possibility that you are wrong.