From what I can make out radfems see two main problems with the concept of transgender. First, it reinforces the gender roles women are forced into, and that feminism aims to dismantle. Second, by allowing a person to define themselves as a woman based on a feeling, it destroys the distinct biological identity of women, without which it is not possible to claim women are a group discriminated against on the basis of that distinctness.
But from my experience of men, the existence of transgender people is never used as a weapon against female assigned at birth women. Though accepting we now treat MtoF transsexuals legally and socially as women, men either still don?t really see them as women or regard them as a category of women quite distinct from FAAB women. In either case transgender MtoFs are so few and far between they have no impact on how men stereotype and treat women in general, treatment which is based on women?s perceived biological identity (even though in reality much of that perceived identity is nothing more than socially imposed conventions).
When men do fight back against feminism in an effort to protect their privilege they do so by attacking its aims and denying there is any need for it in the first place. It?s pretty standard to portray feminists as bolshie women who have a bee in their bonnet about non-existent injustices and who don?t really care about equality and the rights of all, but just want to replace male privilege with their own.
The debate over transgender plays to both those tactics. Most men won?t see transgender as an issue and won?t understand why there needs to be such a fuss over it because it is irrelevant to how they stereotype women. They will also see the radfems treatment of transgender people as clear evidence of how feminists are happy to oppress other minorities when it suits them.
That doesn?t mean radfems (and other feminists) don?t have completely valid concerns over the activities of some transgender people. I can see there are times when they can rightly insist that the needs of FAAB women to have spaces to themselves in which to discuss certain sensitive issues specific to FAAB women must be respected. And when that respect is not given women justifiably get very upset.
But other than that I think feminism would look more reasonable to men, and hence have more chance of influencing their behaviour, if feminists based their treatment of transgender people on respect, compassion and understanding, rather than what, to an outsider, looks like dogma. Because of that I?m glad to see how much mainstream feminist thought does such an approach.