Depends on the women's only spaces. Some of them are meant to protect battered women.
Yeah, keeping spaces gender-specific for abuse shelters or abuse/rape survivor groups makes sense. This goes for both female and male groups.
When my mom, brother and I were staying in a women's shelter when I was a kid, all visitors had to check in at the front desk, but adult males (male children were, of course, allowed to move in with their mothers) had to go through extra checks and whatnot before coming onto the premises as an extra security measure to protect the women/child living there from their abusive exes.
Of course, a bunch of people whine about this kind of stuff, but really, when one of the major at-risk groups among women for being assaulted or murdered are women who are in the process of leaving an abusive partner, protecting them from that kind of harm kind of takes precedence over upholding some vague gender-equality principle.
Mind you, it does get complicated when you factor in lesbians who are escaping an abusive partner. Likewise, for theoretical male shelters (which I'd have zero problem with), being that male-on-male domestic violence seems to be more common than female-on-male. Unfortunately, I don't have a perfect solution, and I doubt anyone does.