In the wake of the horror that is coming out of the github story, I feel the need to once again veer into Ethics 102: Women and Sexism.
This is a bit different though than the last time I talked on this issue. Here's the central point: just because the negative behavior in question is coming from a woman and directed to a woman doesn't mean it isn't sexist. (Yes, it obviously doesn't mean the negative behavior is actually sexist either. See other resources for determining whether a behavior is potentially sexist.)
While women were theoretically granted equality in 1920 with the vote, we are still universally mis- and malrepresented in mass media. Movies and television shows constantly tell us that we are weak, emotionally volatile, dependent, argumentative (bitchy), air-headed, or, most commonly, invisible except as an arm decoration for the powerful men that we can lure into lives. It also tells us that once we hit 35 our lives are worthless since we have lost our only positive attribute, our (supposedly) natural beauty. It is sick.
I don't believe for a minute that all this psychological training is just disappearing when it is dumped on a woman instead of a man. Instead, we develop complex relationships with ourselves and coping habits designed to protect our consciousness from shredding itself. We may work incredibly hard to fight the air-headed stereotype, and develop impostor syndrome as a natural consequence of integrating the training data with who we are. We may develop an inability to communicate our needs because we are afraid of being seen as codependent. We may shut down emotions entirely to avoid being seen as volatile, since any evidence of excitement can be taken as evidence of a "woman's love for drama", or we are simply accused of "PMSing".
But in addition to the above, we may partition ourselves away from other women and then let the negative aspects of the stereotypes be assigned by our subconscious to those women. We tell blonde bimbo jokes. We call brunettes with straight noses bitchy. We call curly-haired women who don't use product flighty, or slovenly. And fat women all of the above. We may separate women from us because they are homemakers, or because they have children, or because they don't have children, or because they have cats.
So all that negative energy pumped into the system by millennia of subordination lands somewhere.
You may say, ah, but how is this any different from the negative impressions of men? Simply put, men have the benefit of numbers and time. There are plenty of smart blonde male CEOs to counteract any real belief in a male blonde bimbo. There are plenty of heavy (and thin) men of every body shape in positions of power and influence. There are men with short hair and long hair and curly hair and grey hair running the world. There are single male entrepreneurs, and family men. There is quite simply plenty of training data available for men - at least straight WASP men. But that is a whole different discussion.
So yes, we women can and do treat other women in sexist manners. We play the Queen Bee or the Princess or the competitive girlfriend, and it is ridiculous.
We women need to stop it.
The female developer community seems to be terribly alert to the misbehavior of men with respect to sexism. But we also need to remember to call ourselves to account. We need to model the kind of behaviors within our gender that we expect from without. We need to treat women from all walks of life, ages, colors, and creeds with the respect they deserve, and stop allowing ourselves to class them "Other" and level them with all the abuse that comes down on out-group women.
After all, women are half the planet. If we can solve half of the problem by ourselves, wouldn't that be a good start?