Yeah I totally don't buy this as an argument for it being across the board ok.
The fact is that in the past, there were so few transexuals that many people would never have actually encountered a situation where they shared spaces.Additionally, they were vetted by doctors as non-dangerous, and most were gay males with no sexual interest in women who often had had surgery.
And what you did not see was such people being in women's prisons, or showers in women's change rooms (or even women's change rooms.)
The situation is totally different now, given that it seems to mean any tom dick or harry is allowed to sit around naked with women and girls in a nude spa and if the women complain they will be told "shut up you bigots", they are often heterosexual males with their genitalia fully intact, have no vetting in terms of disturbing or predatory or false pretenses, and it's all being used as a wedge to justify these male people being in women's prisons, hospital wards, etc. Plus there are far greater numbers.
Gender activism has changed the situation so much that the possibility of the kind of grace that was extended previously is now not only rejected by many women, it's dangerous.