OK, here goes.
I believe that trans women are men.
The reason I believe this is that as far as I'm concerned, "man" means "male person" and "woman" means "female person". Trans women are male people. If they were female they wouldn't be trans women, they would be women. No human in the history of mammalian evolution has ever changed sex.
If you believe that "woman" means something other than "female person", what do you think it means?
Because the way I see it, people who believe trans women are women appear to think that "women" is a category of people which includes most female people (all the ones who believe their gender identity is "woman" or who have no specific beliefs about gender identity but recognise that they are female and call themselves women), except those who identify as trans men or non binary or something else other than a woman, plus a small number of male people who identify as women.
What is the purpose of this category? What do all the people in this group have in common and why do we need a word for that group? Do they all have shared medical needs? No. Are they a coherent grouping for the purposes of sporting competitions? No. Do they all have a similar change of either committing or being a victim of certain types of crimes? No. Do the same kind of clothes fit their bodies? No.
I cannot think of a single thing all these people have in common or a single situation when I would ever need to use a word for that group of people.
I can, however, think of many situations where I would need to use a word that means "female people". A group which includes trans men and some non binary people but excludes men and trans women.
I have come to the conclusion that the ONLY reason why this category exists, the ONLY reason why we need to refer to "people of either sex who call themselves women", is so that people like the male nurse in this case can use women's toilets and changing rooms, and people like Isla Bryson and Karen White can say it is their human right to be housed in women's prisons.
By saying that trans women are women, whether you realise it or not, you are saying, "Female people, you are not allowed to have a word for yourselves, you have no right to have your safety and dignity respected when you are using the toilet or getting changed, you are allowed to say no to men but if a male says he is a woman you are no longer allowed to say no. You are allowed to have boundaries, but only if male people agree that you are allowed to have those boundaries. You are allowed to have the illusion of boundaries, and if that illusion is shattered you must not object because doing so would make you a transphobic bigot."
When you say, "trans women are women", that is what I hear.
If that's not what you mean then I would genuinely like to understand what you do mean when you say "trans women are women".