Maybe banning all men from the community is necessary, or maybe just efficient, to fulfill this purpose.

Yeah, that’s more or less how I see the rule too. Ideally it wouldn’t exist, but without something like it in place, the majority of comments in a women’s issues community would come from men, especially on popular posts. The tradeoff is between creating a community where women can speak to each other on these issues, or including men, some of whom would positively contribute to discussion and have their own relevant experiences to offer. The former isn’t really something that exists on the site and I do feel it’s important to have a community to fulfill that purpose. I don’t see a more inclusive mod policy that’s simple enough to communicate as a rule for WomensStuff, but other communities could definitely step up to fill that role.

The last two bullet points are good ideas and it’d be completely valid imo to respond to a post in WomensStuff in another community including men. (“Guys, how do we feel about this?” kinda threads) !mensliberation@lemmy.ca may be what you’re looking for, it’s primarily for men and masc people but it is open to everyone to comment. There you’d find discussion of issues men face too, and discussion of women’s issues could be framed around how men can respond to them.