Prisoners have to shower together. (That's where all the jokes about soap come from)
I don't want to shower together with even the nicest gay men I know, and certainly not with any strangers, who might not even claim to not be sexually attracted to women.
Forcing women to shower, i.e. be naked in front of males - that alone is a human rights violation.
I would have hoped that, faced with the decision of whether to put a male rapist into a women's prison, common sense and some tiny fragment of, you know, respect of women (ridiculous, I know!) would prevail and they'd decide not to do that to women.
But no, of fucking course not.
Men (and lots of women, sadly) just hate women and have no consideration at all for women, and only care about men's feelings.
(Not so much about men's safety. As soon as you have 2 male prisonser in the women's prison, both of those males are a danger to each other. But they have their genderfeelz validated, hooray!)