Actually I think silence is still preferable to what happens more frequently -- the sexist trolls are actively praised and rewarded in the tech community. Not for their sexism, of course, but for their activism on behalf of freedom of speech, etc. We don't just fail to speak against them, we -- in the tech world -- often hail them as heroes for their other work, while conveniently ignoring the misogyny or writing it off as just "sure, he's not politically correct, but..." or "sure, he can hurt feelings and ruffle feathers but..."

Or the way Reddit is still seen as a "good" place despite a model that not just encourages but needs people like ViolentAcrez. We don't have to speak out about the bad things in order to make a difference... We can start by not speaking FOR the contexts in which it is not just tolerated but subtly, behind the scenes, reinforced. Stopping support for sites that allow this behavior is a huge step that does not require speaking out. Because most sites that "allow" it are also, one way or another, also encouraging it. We get the behavior that we reinforce.