But it has nothing to do with the gender issue. These "jerks" will be jerks to anyone who isn't at their level, male or female - I even caught myself sounding a little condescending today during a group study session.
Women, I think (someone tell me if I’m full of it here) are brought up differently—they are trained to see guys who act this way as threats, and to avoid them, or at least keep their guard up around them. (There are obviously women who act rudely to other women, but it tends to be a different kind of rudeness.)
When guys don't respect social boundaries it can be frightening. Don't be so quick to assume this fear is trained- I didn't start to react with fear until a handful of upsetting experiences. It can be justified fear.
A man who treats women as if their main purpose in life is to be his potential girlfriends has a different problem, and I think most men who act like this are not so much socially awkward as socially mistrained.
Nevertheless, we have very very few female majors.