" Deniers are not the equivalents of flat-earth theorists, nor are they just plain loonies. Theirs is not a cognitive error that can be rectified by showing them documentation or evidence. They are, pure and simple, antisemites, and their agenda is to reinforce and spread the very antisemitism that produced the Holocaust. They can’t be completely discounted. "

― Deborah E. Lipstadt , Antisemitism: Here and Now