None of the women techies I know would be caught dead associating with something like this.
Not saying you don't know them, but I am saying that admitting to wanting to talk to other women has traditionally been admitting to weakness in the workplace.
If women felt liked they belonged in this industry, they wouldn’t form groups like this at all. Furthermore, don’t strawman them by saying you wouldn’t associate with those who would exclude based on gender, ethnicity, etc. The article clearly states that this is a place for women to seek advice and mentorship from one another. Please don’t bring any other factors into this when the article is clearly about a group that is accomplishing a well-meaning goal.
The other group is saying they want equally and accuse the first group of supporting discrimination for having single-sex organizations.
One can accuse the first group of assuming bad faith or the second group for building strawmen, but all that does is signaling which group one identify with. It is unclear how to find common ground when both groups clearly has the same goal but have polarized opinion in how to get there.
I'm not saying that they shouldn't be allowed--go for it--but I don't consider them ethical.
Clearly some women don’t like places like that:
https://news.ycombinator.com/item?id=14702676
As I wrote in a comment on that story, I have a theory: Women-only groups aren’t just “Women-only”, they also exclude women with these beliefs [from the linked article]. But this is far from obvious, so women at these group gatherings see only themselves, and it becomes an echo chamber where they believe they represent all women’s views on this subject.