You're still not getting it.

You don't need to be an authority on anything to know the holocaust happened, in the same way you don't need to refer to a scientist to understand that the moon exists, nor refer to a 'terrorism expert' to know that 9/11 happened. You accept the latter, but you don't accept the former.

That's what makes Holocaust Denial different. There isn't a "second side". It's a rejection of reality itself. It's the only conspiracy theory built solely off of motivated reasoning.

This is why when you push all the way down the line, and move past the rhetoric, you can eventually get a Holocaust Denier to admit: that they know it happened and it was a good thing as far as they are concerned.