This line of reasoning seems to assume that it's sexism that drives women away from tech. But most people chose to go into a technical field when they're still in high school -- long before they would have encountered the sort of workplace/conference/community sexism people gripe about. Colleges have historically had a lot of trouble attracting girls to their technical/engineering programs, despite often bending over backwards to try to improve their ratios.

Isn't it possible that there are other factors which cause such a large gender disparity between choices that teenagers are making...?