I advise women who need advice for the specific gender obstacles they must defeat. (Obviously this is a perverse situation and the first order of business is to find women they can speak with. But its not easy to find trailblazing women.) If you face an obstacle, it's irrational to ignore it. You learn, plan and defeat it.
Wanna see a men's only club? We have some at my workplace — management, dev teams, etc. Same with other companies I work with.
Sexism is about a power dynamic: men dominating women. Male supremacy. Since men benefit and perpetuate it more than women, women's only clubs are simple self-defense against a system loaded against them. (In favor of mediocre men.)
BTW, men often reward women who act like "one of the guys" and snipe at other women. Makes men feel better about their prejudices; gives them an example to point to of how proper women should act.