[0] https://tmhdc.org/ [1] https://www.thecut.com/2015/03/why-i-live-in-an-all-women-bo...
(and those two links took all of 15 seconds to find)
Have you verified that TMH is female only (not self-id based)? If not, what makes you think it's female only?
It's understandable if you assumed "women only" meant "female only" (as that's what most people understood it to mean from forever go up til about 10 years ago) but you'd be mistaken if you thought it was that simple. In many (most?) cases these days, "women" = "self-identify as women" which means it is not a single sex facility.
Not everyone is from the US or a Western country.
The broader question is would it be allowed even with that. If it was done for safety reasons, you can make an argument that it’s discriminatory towards men because you are assuming they will be violent. Pretty sure the same justification was used against black/poor/immigrants/etc.
If it’s not for safety reasons, and just a thing, could you enforce it? You can create a place called “A Woman’s Space” but would men be legally allowed to go?