i think he single-handedly invented the field of sociolinguistics with the publication of his master’s thesis, so his genius as a linguist and social scientist is not in doubt. but that was long ago and he has since transformed himself into a left-wing public intellectual who takes great care not to be outflanked by anyone else on the left (i.e. no one can be more left wing than he), so as a catholic i find him to have substituted politics for religion. he wants to be the pope of his own man-centered religion.
i’m not a great chomsky-watcher, but he seems like the type who never acknowledges a mistake and who gets into long acrimonious arguments with people with whom he disagrees. watch out for that type of person (for the first reason especially).