Okay, I have definitely not read the entire thread, but I would like to add some positivity in here, from personal experience. I myself am not a woman, what I can share is my experience in both the local go group and chess club, as those differ in very interesting ways.
The go group consists of about 10 people, where usually around half of the attendees are female. It is a small university group that came into existance by a bunch of people, who had no idea what go is, but found the news about AlphaGo interesting and wanted to check out the game.
The chess club, on the other hand, has existed for many decades, has regular meet-ups, a few teams competing in local leagues, and has most notably not a single female member.
Now I know that mentioning chess in go communities is often frowned upon, and vice versa, but for the sake of the observation, I would assume that both games are sufficiently similar, as that either one wouldn’t be more appealing to a certain gender than the other.
My observation has been, that whenever someone new joins the go group, regardless of their gender they usually fit in with the social dynamics of the group. It has happened that people sometimes do not fit in, of either gender, which, as far as my observation goes, has been due to them wanting to check out this game they have heard so much about, but eventually not finding it interesting.
In the chess club, however, there has once been a woman who came to the club meetings, with interest of joining the club. She was already quite a strong player, so there was no boundary in the sense of spiking her interest. I perceived her attendance as very discomforting for most other members. Usual non-chess topics, that would be discussed in a male-only gathering would be the arguments one member has had with their ex-wife, how nice it is that a nice attractive young woman started working at the grocery store in the street of another member, and in general which traits in women are determined attractive.
I wouldn’t deem any of the chess club members as sexist. I know that some of them actively support programs for women in chess, and they actively try to include games from female professionals when analyzing pro games at meetings. It seems to be the general atmosphere that comes up with an overwhelmingly male majority, concerning off-topic, small-talk discussions, that is hostile towards women.
What I would conclude, humbly, is that even in the complete absence of sexist intentions by anyone, the social barrier to pick up go is just stronger for women than for men. I don’t come with a solution readily available, but given how meaningless gender seems to become, when all are present, I want to claim that actively creating comfortable spaces for women in go, i.e. meetups, where other active female players are present, might come a long way. After all, I probably also wouldn’t have started out playing, if it weren’t for my friends, with whom I had a good time discovering this game.