‘Take that you humorous rabble!’ Hitch was poking fun at the fools sitting in leftist judgement.
Well, he clearly refers to “the sort of people who do not read the New Yorker, or go in very much for the ironic and the satirical” with every indication that this stereotype is not the object of his taunting but that he too believes it.
Hitchens is a leftist with purely leftist thinking, what makes him act differently sometimes is that he enjoys being oppositional.