Luckily he's shooting himself in the foot, but Atrios is right:
The trouble is, the professors in these cases cannot defend themselves with the facts about these cases. They aren't allowed to go to the media and say, Listen, little James did this, actually, and the test question was this, and this was his answer, and here is actually why I gave him a D.
The professor can't even say whether little James got a D or not.
The professor can't even say whether little James was actually one of her students or not.
It's called the Buckley amendment. We can lose our jobs if we say one damn thing about little James.
And little James can say anything he wants to about us.
So some student goes to Horowitz with the wholly bogus claim that her professor gave her a midterm exam question: "Explain why George Bush is a war criminal," and when she, ardent patriot that she is, instead argued that it was Sadam that was the evil war criminal, her nasty liberal professor gave her an F.
Horowitz travels all over the country for six months, whoring this story to Winger audiences and to legislators, making God knows how much in speaking fees, I might add, and the only trouble with the whole speech is that it's a flat out lie.
See these sources for details:
In 1213, our basic Freshman comp course, we teach our students to check their sources. Why didn't Horowitz check his sources?
You have to wonder about that.