In other words, he has enough common sense to curb his ideology.
I have no idea of Chomsky's anarchist philosophy, but I have to acknowledge that he is one of the most useful and productive sources for liberals and radicals of all types. In this sense, his social-democratic impact is far more important than his philosophical stance, so there is something to the idea that his anarchism is not very relevant to his contributions, most of which, by the way, do not hinge on him being able to count.
MBS