You're right. There is also something implicitly sexist in claiming that the gender gap "hurts republicans", since that assumes that it is women who diverge from the "norm" which men represent. Not that I think Snowstalker is sexist, at all, but I think his essay (which is pretty good overall) is very poorly worded in that regard.
The assumption that men are normal and women are different is a very pervasive one in media and culture. While the sexist undertones are deeply troubling, it's hard to fault someone for not really recognizing them in a given context.