Well I see a lot of posts where people proclaim they utterly reject the idea that somebody could think they were born in the wrong body
I fully understand that someone can feel that their body is wrong: bodily dysmorphia. IT's a feature of anorexia, or people who feel they should not have a limb which they have.
Thing is, they're not necessarily correct.
We don't tell anorexics that, yes, they are fat and that they should go on an extreme diet.
Feeling you are in the "wrong" body is a problem of mental perception; it's an illness - dysmorphia - not an actual material thing. People need therapy to help them feel less did-ease with their bodies.
In the 1970s, part of the therapeutic response for people then called transsexuals was to try some bodily modifications, in order to help people live more comfortably with bodies which repelled them.
This doesn't necessarily "fix" dysphoria/dysmorphia. It was an experimental therapy at the time - and, in my opinion, remains so.
And the whole thing is so predicated on the Western notion of a split between mind & body - a concept which is harmful to us all.
PS. Do you think discussing menstruation is transphobic? Because that's what women are being told ...