Does no one else bring their partners?
When I went to these groups there were a lot of men there.
I personally completely disagree with men being allowed at these sessions for the same reasons as you.
Perhaps they could put on a couple extra sessions for the men or even female partners to me included but like you say these should be safe spaces for the pregnant/BF women to open up.
I also disagree with men being allowed to stay overnight on maternity wings.
However, is this group just for mothers or can people bring their partners?
It actually sounds like this is a group where partners (and therefore men) are allowed which means you have no right to not want this one man there for the reason you state, if other men are there too.
If it is a group where no partners/men are allowed then I would absolutely complain about this person having different rules.
But you cannot complain about a male being there if it’s not a female only space.
I actually think if you’re honest with yourself it’s probably more to do with them being trans and a biological man wanting to BF (which I understand).
It’s a difficult one because you are wanting to exclude this one man, even though it seems men are welcome to attend the group as well.
I would not be ok with it but then I’d also not be ok with the others bringing their male partners either.
At the end of the day, they are trying to make sure their baby gets the food and nutrients it needs like the rest of you.
I personally don’t think a man needs to BF but your argument is that you want a female only space to talk about intimate things, but it’s not a female only group because partners are allowed.
If it was a female only space and this person wanted to attend, then it would be an issue and a very challenging one to get around but it’s not a female only group.