It is unsurprising that academics, at least the lazy ones, would arrive at the conclusion that the left tends to the irrational and the shrill, whereas the right does not.
After all, it is on college campuses where we find the shrill, irrational, fringe of the left ascendant. If you look no further than a few yards from your office, you will find centrists of all stripes being shouted down by left wing fringe elements. You might, if you were either a dimwit or a right-leaning libertarian troll, put this wildly narrow world view forward as some universal truth.
If you look a little further, you will find that you're simply not seeing the right wing fringe. They're around, just not on college campuses. They prefer internet forums and their own network of wild-eyed foaming web sites. You'll find them on internet forums belittling everyone who disgrees with them, insulting the other side (and in forums where they are not yet in control, they will do it carefully, smearing "generalized groups" rather than individuals, and avoiding the use of a little list of words that have been ruled out by the impotent and naive moderators).
What you will not find anywhere, be it college campuses or internet forums, be it left or right, is fringees having actual discourse. Nope. They will simply state their positions over and over as if they were obvious truths, often claiming exactly that; they will attack whatever and whomever they perceive as the opposition by whatever means necessary, while painting the whole thing as a free exchange of ideas. Then, when the wheels fall off and people have had enough of the thinly veiled insults, the barely translucent instigation, they will spring back in horror, declaring that this was Never Ever What They Wanted. And then they'll do it again. And again. And again.
The name of the game on both sides is to smash the discourse, shout down the centrists, and destroy any attempts at reasoned debate.