Joseph:
It’s not like they’re learning gemara. Nobody ever said it’s assur to tell a woman how to keep kosher, Shabbos, etc.
I personally also don’t really see how it was such a big chiddush to have girls going to Jewish girls’ schools instead of public schools or homeschooling (presumably the alternative). The wikipedia on it makes it sounds like, at the time, girls had gotten so stupid they didn’t even know how to keep shabbos and therefore they had to start it as an emergency. I don’t buy that.