This is what Wiki says:

"The scandal largely related to the inclusion of an essay by American linguist Noam Chomsky, entitled "Some Elementary Comments on the Rights of Freedom of Expression", as an introduction to Faurisson's book, without Chomsky's knowledge or explicit approval. Responding to a request for comment while Faurisson was being widely attacked for his book, Chomsky defended Faurisson's right to express and publish his opinions on the grounds that freedom of speech must be extended to all viewpoints, no matter how unpopular or fallacious. The affair generated controversy among scholars both in France and the United States."

I would have been peeved if someone published my work without my permission, but Chomsky was defending free speech not Robert Faruisson. I find it hypocritical for anyone in the United States to bring this up in the light of of Tumpists and the Alt-Right's insistence that they say anything they like no matter how many lies or misrepresenations are invovled.

So basically, if one wants to call Chomsky evil on the basis this, should we not call Trump and his every supporter evil?

You must agree that they are an ignorant vile lot !