Libfems, the stalker subreddit, and TRAs in general often chant that the existence of trans men makes all "T*RF" theory collapse. They only say that because they have only a superficial understanding of what radfems believe, and they've mostly been exposed to cherry picked examples of people using GC theory to further actual transphobia (stuff like the people who say literally every trans woman is a predator-- obviously if that was the only thing at hand then trans men wouldn't exist).

To clarify, I can only speak for myself really but I consider myself a radfem and I would absolutely include trans men and "AFAB" non binary people in my feminism. Obviously many (most?) of them won't want to be included, so I won't force it on them or anything, but I believe the goal of feminism is to fight for the rights of women as a sex class. I think oppression is based on something you can't change, and you cannot literally change your sex, therefore I still think trans women and "AFAB" non binaries are oppressed on the basis of their female sex.

There have been several recorded cases of men (both trans identified and not trans identified) raping pre/non-op trans men; male on female rape is inherently more dangerous and harmful than other forms due to the risk of pregnancy and the difference in physical strength between the sexes. In one case a trans woman raped a trans man while saying that they wanted the trans man to "have [his] non-binary babies". Even for people who claim to transcend biological sex, the laws of nature don't change.

So even if they don't want us to fight for them, I will fight for the rights of trans men. I don't think they're all confused lesbians or "betrayers of womanhood" or whatever. Some are indeed self hating lesbians or just self hating women period -- detransitioner stories tell us this. However I also believe that there exist trans men who have gender dysphoria and feel happiest living life "as a man", and I support their right to live their life the way that feels authentic to them.

Anyway, that was a huge foreword (mostly targeted at stalkers/lurkers) just to say: I find the focus on trans women to the exclusion of trans men in the trans movement a very telling example of how bio sex matters even in spite of gender identity. This prioritizing of trans women over trans men happens at all levels and in all directions (internal and external supporters). I can think of no other group of people for whom women's voices and concerns are consistently prioritized over those of men.

In my observation, the most prominent trans men (people like Buck Angel, Calvin Garrah, etc) are all realistic/accept that biological sex exists. It is more the trans women who want to pretend it doesn't exist. This to me strongly mirrors how white people say they "don't see race", whereas no non white person would say the same. When you're oppressed for something, you know you can't just ignore the reality that it's there.

The fact that "trans women are women" is a slogan while "trans men are men" is not (except as a half hearted after thought, ONLY after "trans women are women") is another sign.

The fact that r/askgaybros and other gay men subreddits are allowed to exist while lesbian subreddits are banned and the "trans inclusive" one left standing is overrun with "transbians" who dominate discourse, make every topic about their "girldicks", constantly require validation, etc.

The fact that we have people like Amanda Jette Knox gaining praise for centering her life around her male spouse's "journey to womanhood", whereas the "trans widows" are shamed -- women must stand by and support their man no matter what. But what of trans men? Where are the droves of middle aged moms deciding to go on T, grow a beard, call themselves "Aiden"? Imagine if these trans men actually existed -- what do you think their husbands would be expected to do? How many of their husbands would brainwash themselves into thinking they're gay? Or be shamed for not being 'supportive' of their spouse?

The way trans men are ignored, cast aside, and diminished by the very people who are supposed to be their community to me is just further stronger evidence that biological sex matters in a way one can't simply "identify" out of. The way women with families virtually never become trans men shows to me that biological sex matters.