People have been long speculating that sexism was a much more common problem than exposed here. For a long time, I had been thinking the problem was exaggerated, since it was never part of my experience in companies I worked for. However, from my limited interaction with these involved guys, I've never imagined they could do something like this. Maybe I've never felt this problem just because I am a male. Maybe this is part of the culture in Silicon Valley after all.
It is true there are predators all over the places. That doesn't give any excuse to these guys. As one of the most liberal places, Silicon valley holds a higher standard than the rest of the country.