I should clarify a little; the official "Feminist Theory" (as determined by English departments in universities...well possibly as determined by Gender Studies departments and used by English departments) is anti-violence. I've actually had a prof tell me that Buffy the Vampire Slayer is not really accepted as a feminist work.
Now, the academic use of the word "feminism" doesn't necessarily match up with the real-world. As it happens, I like Buffy the Vampire Slayer, and don't really consider it to be a poor portrayal of women. And yes, I agree that self-defence classes are a good idea (although the thing with "self defence" is that, at least on paper, it's defence. It's different than being the aggressor).
And...now I'm just veering into a different topic, but domestic violence is an interesting issue, and not necessarily as gender related as people assume. The lesbian community actually has problems with domestic violence to the point that they put up posters for domestic violence support. You don't see posters for gay males...EXCEPT that from what I understand, domestic violence between gay males generally goes unreported. If you do call the cops, apparently they tend to respond with "oh ho ho, just a couple of guys having a scuffle. Break it up, boys." And then you have domestic violence towards men from women--this is a friend of a friend situation, but apparently one guy was getting beaten by his girlfriend, called the cops, and the cops arrested him, not her. "Domestic violence? Remove the man from the situation. PROBLEM SOLVED. High five, let's get doughnuts."
Okay, enough with that tangent. The interesting question is why academic feminism would take in the apparently unrelated anti-violence stance (beyond the realm of domestic violence). One answer that jumps to mind is that physical combat is an inherently unequal arena; wereas verbal conflict is fairly equal (women score higher on verbal tests, men have louder voiceboxes). Another answer is that the academic leaders in feminism are women, and standard brain psychology differences tell us that, for example, if a bunch of boys walk into a computer room, they'll scuffle for the best computer, whereas a bunch of girls, even amongst themselves, even back when kids are of equal strength, won't use physicality to solve the problem. (The evolutionary theory I've heard is that women spent a lot of their time pregnant...where shoving for a small gain is just too risky). So...get 100 such feminist academic leaders into a room, and then suggest "shoving is bad" and you'd get a lot of head-nodding and "that feels right to me", even if an anti-shoving stance doesn't do much to advance the female condition in the year 1990.