Well I can answer some of that from an evolutionary psychology point-of-view:-)
Holding the moral high ground probably comes from the same base instincts as territorialism: You stake your ground and are prepared to fight for it.

The really tedious attitude of academia and experts, that only they can be right, so you are wrong unless they say you can be right, is the flip side of the same thing. They are fighting the ground they have already staked. From an animal point of view, the fact that they are often wrong is irrelevant. They invested a lot of energy into the current position and don't want anyone outside the tribe to undermine it.

If I ruled the world I'd make all academics study EP, then they might think twice about behaving like wankers... which is, of course, also natural.