You should research feminism in general and diversity movements in technology some more. Also Lynn Root's talk at EuroPython was a good recapitulation of current diversity trends.

There is evidence which prooves discrimination and unfavorable bias against women in technology. Therefore, there is nothing wrong with creating organisations for women.

Fact is, several DjangoGirls "graduates" who have never done any programming have gotten programming jobs within a year. So apparently, there is some benefit to their on-boarding and motivational efforts.