>Holding "women for CS" events only makes the women in CS feel even more isolated from their male peers

I don't think this is true at all (and usually you never see women say this, just males rationalizing their position). Women centric CS events are to encourage those who have an interest but may have been hesitant for some reason to seek it out. Or to encourage those who are students to seek help and find comraderie/validation.

A common theme from women is that they often feel like imposters in intro CS classes because its always guys who seem to be so much further ahead. Of course, guys will chime in that they experience impostor-syndrome just as much. The difference is that girls have an immediate re-enforcing explanation for that sense of being out of place: you don't belong because you're a woman. This is the curse of being a minority in a field that you aren't well represented in. This is why these CS-centric events are important.

>The difference is that girls have an immediate re-enforcing explanation for that sense of being out of place: you don't belong because you're a woman

How is this different from guys who go, "They're so ahead of me. I'm out of place, because they are all smarter than me"?

Exactly my thoughts. Most of the people I've spoken with honestly in my CS classes have expressed these feelings of inadequacy. Often it's accompanied by things like "oh, I didn't take CS in high school and it seems like everyone else did." If they're a certain gender or race they may feel this has hindered them, even though many others in the class secretly have the same feelings of inadequacy.

I'm not sure whether it'd be comforting to feel (correctly or not) that your background is partially to blame for your lack of confidence or success. On the one hand you may discourage yourself and set yourself up for failure because you believe you have a good reason to fail. On the other hand it may prevent you from beating yourself up as much since there are some external factors at play that are out of your control.

It's different because people around them are more likely to react as though not being good at CS is an expected outcome of their identity: http://xkcd.com/385/

Beginning guys who find themselves in classrooms full of people that started programming in their teens do what they always do - suck it up or fail. Such is the life of a member of the majority.

It's perhaps also worth noting that sexism and discrimination are usually just as bad for members of the dominant class as they are for members of the discriminated.

Programs which would help more women be involved and included in CS will end up helping men who would find themselves in similar situations. Discrimination is harmful to just about everyone.

Are you saying that that's a good thing? I'm not quite sure of the intent of this post, so I'm not sure with what tone to read it.

Subculture is relevant. Sometimes the borders of subcultures can follow gender lines. Sometimes such borders are arbitrarily hostile.