Jesse says he (sort of) agrees with Horowitz that academic disciplines can have political biases and perpetuate echo chambers of falsehoods. I'm not sure I entirely disagree with that point. Although I'd have to say there's plenty of disagreement within the women's studies community. That is the point of academia -- to constantly revise to get to the truth. The one economics class I sat through when taught by a George Mason professor was loaded with debatable assumptions and lots of free-market biases. (Although I doubt Horowitz rejects economics in the same way he rejects women's studies.)
What I do think is that Horowitz picked on women's studies (or, as I prefer to call them, gender studies*) departments for a reason. As one of the newest disciplines and loaded with social stigma that just isn't true of other humanities or social science disciplines, he used biases rooted in sexism to make his larger point about academic freedom.
Leaving aside the obvious point that I am a woman arguing for gender studies against two white men, I have to disclose that I was not a women's studies major in college and never took a class through the gender studies department at my university, but I do identify strongly with some key feminist works that are usually required reading in the department. I can't speak to Jesse's experience in a comp lit class at his college, but my instinct is to say that sure, there are biological differences, but it's also true that people have massively overestimated biology's relation to gender over time. It used to be widely accepted in the scientific community, for instance, that women could not play sports because it would damage their uteri. Therefore, I think the point his teacher was (hopefully) trying to make is that assumptions about biological differences aren't necessarily a given and we should be really careful about throwing them around.
Personally, I wish I had taken gender studies classes at my university. I think I'd be better off. In fact, it's arguable that everyone should take a gender studies class as part of a liberal arts education -- or even a regular high school education. After all, the way gender plays into culture is relevant to everyone. I reject the idea that gender studies is an inherently "political" discipline any more than other social sciences, but it is definitely perceived that way. That's why Horowitz chose it. He used a political perception about women's studies to make a political point about academia in general.
*I know this is controversial, but the reason I favor gender studies is mainly to be inclusive to transgender individuals.