Um, women aren't missing out on anything either. They are just as free to attend the same industry events as men.
Why? Seriously.
Because you're a dude? Have you been to mostly-women gatherings before?
I believe that if people go to an event expecting to be treated as an outsider, they will behave in a way that will discourage people from welcoming them.
It's true that some number of guys have treated some women as lesser beings at tech conferences, but it's also true that some number of guys have treated other guys as lesser beings at tech conferences. Geeks are competitive and cliquish. It may be that way with people into crocheting, too; I would almost expect it. But my experience has been that most people are pretty accepting if you show some persistence and genuine interest.
What I don't see mentioned much in the discussion of women and tech gatherings is that a whole lot of guys feel awkward and unwelcome when attending tech events.
That doesn't necessarily mean there's no misogyny, but it suggests that the feeling of unease people feel is not (always) because of sex, but because some groups just are not so welcoming of outsiders until the outsider demonstrates some chops or other sign of "belonging".
How many times have you skidded away from attending an event (professional, social, whatever) because you didn't know anyone there? How many more would you have avoided if you knew everyone there was Not Like You, in some fundamental, if suck-it-up-able, way?
I'm still on the fence in terms of whether minorities (numerically in this industry) deserve 'special treatment' - but if members of a minority choose to reach out to each other (networking events, dinners, scholarships), who are we to criticize?
In any case, I'm not criticizing, just pointing out a bad argument. They can have their little Ruby on Rails "you go girl" event, I have no desire to go. Although I've never attended such an event, I'm told they suck; {Good AND girl} is a much smaller set than simply {good}.
But suppose you are right. Simple thought experiment: take a workshop, and throw away half the good people. Is the workshop just as good as before?
If by throwing away half the prospectives, the remaining half can learn faster or more comfortably, then I'd go with "better", not "just as good".