It's nothing new and I'd imagine it goes on from both sides (I don't really get much Pro Right up here though, as you could imagine). But, of course, I'm talking about college here.
I just hope people don't come off with the idea that all professors are like this. I've got a sociology teacher (of all things) who constantly plays devils' advocate for the right (most kids are left), and a geography professor who, though he constantly talks about politics (it's a political geography type class), I have no idea as to what his personal views are.
Then again, I also have a history professor who stumbles upon Bush every class in some way or form, but the guy's 80 years old or so and bordering on senility, so it's just amusing. Even so, history teachers need to be able to compare and contrast (hopefully, from a neutral view, but that's tough for humans in general).
In highschool the only real agenda I ever ran into was from a very sweet Jewish woman who found a way to incorporate the Holocaust into every required reading for English class. IMO, that's not a bad lesson, and the books are in English, so no problem there.
This guy though, if the allegations prove to be true, is way over the line.