Chomsky had long publicly criticized Nazism, and totalitarianism more generally, but his commitment to freedom of speech led him to defend the right of French historian Robert Faurisson to advocate a position widely characterized as Holocaust denial.
Without Chomsky's knowledge, his plea for Faurisson's freedom of speech was published as the preface to the latter's 1980 book Mémoire en défense contre ceux qui m'accusent de falsifier l'histoire.
Chomsky was widely condemned for defending Faurisson, and France's mainstream press accused Chomsky of being a Holocaust denier himself, refusing to publish his rebuttals to their accusations.
And how do you know they are real? Because historians have been free to dig around and publish arguments and rebuttals and evidence. Not because anyone by decree or force declared it to be so.
