"Sounds like it's a job problem, find another job" - I've had over 6 jobs in my field. The longest for about 3. These patterns are all the same everywhere I go. I am good at what I do and so I join companies with other people like that - that's the only thing in common.
"I can't comment because I'm a man so everything I say will be sexist" - Not true. Acknowledge that there are people who feel this way about the industry. Until we can have a conversation about it, it won't change.
"It's not a gender problem, it's a culture problem" - Never claimed this was a gender problem myself. The type of work encourages these types of people to congregate. That, in itself, is a problem. We're trying to increase diversity in an environment that is not diversity-friendly (from an interest/perspective.)
"Learn to manage your communication" - At this point, I am a master of working with men, but I have to work so outside my nature. Keep it cold enough so it's not perceived as interest, keep it warm enough so I am not perceived as a bitch. It's a thin line that, to be honest, is exhausting to walk the whole time.
"Women don't love CS" - Wrong. In my department 80% of women quit after the first few years and most cited social reasons for it. You can take a liberal arts class where you can have intellectually stimulating conversation or you can take a CS class where there is rarely conversation about things outside of tech. I imagine that's hard. I loved CS, but I always needed to get out.
"Get outside the work circle and find other friends" - Sure, of course I have them, but as startup culture goes you work 9 to 9 sometimes. What are you supposed to do? You spend more of your time with your coworkers than anyone else. Why shouldn't you reflect on how that environment makes you feel?
"Is this a post about gender issues or startup culture?" - It's both! They are not separable. The culture, because dominated by men, creates an environment that is not necessarily pleasant to women. When the only answer is to get more women in, you're in a catch 22.
All other mean comments about this being a sympathy post or a disgruntled employee, read more carefully. Random negative comments only reinforce what I'm saying.