A very puzzling point of view. She claims to have been harassed all along at GitHub while she was promoting it. This goes to show the limitations of the twitter platform for serious discussion. I'm sure she'd have a more logical case to make in >140 characters. Twitter is the easiest platform to vent on, and that is precisely why it should be avoided in such circumstances.
"I regret defending GitHub's culture to feminists for the last two years. I'm sorry to everyone I've hurt in doing so."
"I've been harassed by 'leadership' at GitHub for two years. And I am the first developer to quit."
Worse than having a serious discussion on twitter, though, is tweeting twitter as a source of breaking news.
She's either currently faced with an unusual situation that doesn't reflect githubs normal behaviour, or she had no credibility in the first place.
At this point, she seems disgruntled about a single issue and is using it as a platform to stir up wider controversy.