Maybe he was/is too cerebral or fragile to deal with others immaturity. We saw it on Hard Knocks when they dubbed him "big wierdo", clearly his personality did not mesh with the jock mentality that would appear to exist with the other so called idiot professional offensive linemen on our team.
Maybe two years of this and a demotion was the final straw and if that is the case I don't blame him, there are at least two of our linemen who are jerks, one we always knew about and the other we are perhaps just finding out about. That said the coaches should have recognised this and dealt with it...