I don't think he's insane, I think it's largely an act. Supposedly, in private, people that know Beck will tell you the same thing. He's a political shock-jock. It's especially evident when he fake cries... probably an ENFJ.
Though, he is a Mormon.
He is so blatantly fake that it is difficult to imagine anyone not seeing it. He does act mildly insane, though.
The first man to raise a fist is the man who's run out of ideas. H.G. WELLS
The first principle is that you must not fool yourself, and you are the easiest person to fool. FEYNMAN If this is monkey pee, you're on your own.SCULLY