Like the fact certain types can be used to basically justify anything the majority likes, regardless of whether it's really fair on anyone else. You could argue banning various social and religious views is acceptable as a utilitarian, so long as the majority of the population would be happier with them banned.
> "No, because the suffering of the women will inevitably be greater" IMO, this is obviously true. Why wouldn't it be the real reason?
Yes, that really is the reason it is wrong. Men aren't utility monsters, the existence (even hypothetically) of utility monsters is doubtful, and it is harmful to optimize a system of morality for situations that have an infinitismal probability of being realized.
is that something you actually support, or am I misinterpreting?
There's definitely a place for morality, but perhaps a better way to put it is that there should be no place for any non-utilitarian morality in any legal framework.