People have the right to be wrong
Have you ever spoken to a Holocaust denier? If you ever get such an opportunity, I highly recommend it.
They will mention vague but inevitable historical anomalies. They will point out already long-debunked notions of non-existent gas chambers. They will say that, yes some Jews died, but then so did lots of other people. They will, sooner or later, bring in the phrase 'Holohoax' and invoke this stupid neologism as a sign of their daring, iconoclastic wit.
I've spoken to several of these clowns and while some are just sad, and some are bad, they are all mad. Ultimately, spending time in the company of a Holocaust denier is to spend time in the company of insanity.