Pitcavage is a very far left critter, almost as bad as that other Mark in SPLC, Potok. His academic credentials have been smacked rather ragged, and far as I know he deserves it.
His closest ideological friends, I think, would be Devin Burghart and Leonard Zeskind. You can find them here:
Wow, that’s a name from the past. Wasn’t he the Lefty professor who spent tons of time in newsgroup (nntp) political discussions? I forget the details of his favorite subjects. Likely defense of Clinton, given the era I’m remembering.