What on earth...
One thing I've learned from my run-ins with these types of radfems is that with sufficient mental acrobatics, they can believe nearly anything.
They start with a worldview that says that male oppression of females is the most primal and worst form of oppression, and that all other forms of oppression came secondary - academically dubious but not entirely wrongheaded. They then progress to the specific source of that oppression, which they hold to be sexual in nature: penes oppress vaginae.
Trans men get virtually no focus by these radfems or their sympathizers. They won't get their identity respected, but you'll often hear anti-trans folks say things like "I don't care very much about [trans men], it's the [trans women] that are the problem."
Because to them, males are defined by penes-at-birth and females by vaginae-at-birth, and it is impossible to change your sex. Thus, trans women are just Privileged Patriarchal MenTM trying to claim even more from Womyn Born WomynTM. And they sure use an impressive amount of No true Scotsmans and other fallacies (Brennan herself once claimed that "no female would ever go after a child," for instance).
They see everything as patriarchy. All movements besides Women's Lib are, to them, insidious patriarchal attempts to oppress women. This includes the LGBT movement, which they tend to decry as not helping lesbians enough and focusing too much on changing society's attitudes toward attraction and identity (vis-a-vis queer and transgender theory).
so seriously, how do they deal with "vag to penis". something along the lines of "you betrayed your sex?"
More like "butch turned up to 11" from what I've seen. But keep in mind that trans men were allowed at Michfest, a famously womyn-born-womyn event, up until quite recently.
I had a long rant there, and then thought "fuck it, that's beside the point".
Dismissing trans women as privileged males in disguise is an interesting perspective I hadn't considered, though. Not sure, possibly more that they're confused by the concept of sex and gender being non-absolute. If you build your whole identity around being an Oppressed FemaleTM then trans seriously threatens that identity.
Yes. Well, they believe that gender actually doesn't exist/have meaning and is something of a societal delusion. Sex, to them, is absolute and inviolable. Germaine Greer and other radfems infamously like to proclaim that anyone with atypical genitalia is male, and only those born with the "perfect" female genitalia are truly female.
It takes you into a bizarre world where you ask the question, "What defines a woman?" to both militant misogynists and radical "feminists" and you get the same answer.