Transwomen are not women. Humans are sexually dimorphic, therefore transwomen are a subset of men. Invoking the individual vs class distinction, whilst on an individual level I may make a decision as an individual to use a MTT's preferred pronoun, on a class level they remain 'he' and it is accurate to refer to them as such. And, as such, I reserve the right to use my language accurately to refer to any or all MTT as 'he'.
As MTT are not women, they are not entitled to access women's protected spaces, or stuff that is earmarked for women - whether that is college places, grant money, or women's sports. They should not be counted as women when looking at issues of equality, education, crime, or health. The issue of discrimination MTT face and any risks from male violence needs to be tackled separately and it is not the business of feminism to deal with this. Whilst individual women may choose to be involved with this (and I would certainly support this) it is not the business of women as a class to make this right for MTT. It is neither necessary, nor honest, for MTT to claim they are women in order to secure the rights due to them nor the safety from violence that should be guaranteed them.
Calling any individual MTT 'she' is very often the thin end of the wedge. Starts with a pronoun, goes on to using the word 'woman' or 'girl', and then after a short while, bang. You're in the mess we are currently in.
My personal latitude re pronoun use is actually irrelevant. It has be one rule across the board, which means that if 'she' is to be used of any MTT the sentence 'this woman committed rape with her penis' has to be acceptable and meaningful. (I consider that if any MTT is a woman, then all must be, including eg Danielle Muscato, but if you prefer to cling to the notion that only those who have had 'bottom surgery' are deserving of 'she', then the meaningful and accurate sentence needs to be 'a woman committed rape with the penis that she used to have'. Still meaningless.)
And why the focus on willies? How is this fair? Helen alluded to the fact that surgery is booked for November. I like Helen and want to be accommodating. So, do I call Helen 'he' up until November, then tactfully ask if the chop has happened and if it has use 'she'? How does that work? That's a pretty horrible way of going about things. And anyway, I thought we had decided that a woman is not simply a bloke minus the nadgers. In that respect I think TA are correct - it's all or none. I say it's none, they say it's all.