Really I have yet to see a valid reason to not put a trans woman into a female prison.
That sentence simply does not compute. There are many valid reasons on both sides of this argument. To state otherwise is disingenuous, at best.
Given that, it seems, that many trans men and women choose not to have lower body surgery, that GIRE advise that genital surgery should not be regarded as inevitable there are many people for whom a wide range of places, institutions etc become an absolute minefield.
It s not wrong for a pre op trans woman to want to use all sorts of women's facilities.
It is equally not wrong for any (sorry in advance, I hate the term) cis woman to feel uncomfortable, to object, to that happening.
Neither side of that argument is 100% right or wrong. Nor is either side of the trans male equivalent.
We don't need more bold statements of right and wrong. We need more knowledge, more normalising of either trans situation. Leading to a more effective use of that wide range of facilities that makes any and all people feel safe.
Simplistic statements don't help. They just make the gap between the 2 black and white perspectives larger.