Well, he is not denying the Holocaust in essence: deliberate, utterly evil mass murder of Jews based on their ethnicity alone. I agree that the numbers he is throwing around are ridiculously low.
My point is, he is not an idiot; I read some of his writings on other subjects and he is a thoughtful man. Is he also an anti-Semite? Possibly, even though he denies that.
I think the key to my point is "mass" murder. He's off by at least one order of magnitude.
Worse still, I believe he denied the existence of gas chambers at Auschwitz (note that he attributes his views to Leuchter, who made that same denial).