Respectfully, in my personal experience this hasn’t been the case- although the part about transmascs being seen as “corrupters of young girls” alone is indeed very true. The part about people born with vaginas never being treated as sexual predators is a really common misconception I see a lot, but I think you’re trying to discuss it in good faith, so I will offer my perspective here. I think this misconception is rooted in a combo of erasure of transmasc struggles and erasure of lesbian/sapphic struggles, and the assumption that these groups somehow have it easier, when really people just don’t talk as much in the mainstream about the problems we have relative to more hypervisible queer people (not saying we have it worse than hypervisible queer people though, just to be clear- just that we do face similar types of bigotry but it’s rarely acknowledged or discussed).
Cishets can’t fathom a person born with a vagina being a sexual predator if that person is gender conforming. BUT if you’re perceived as a GNC person who is “supposed to be a woman” (in my experience as a butch who was raised as a girl in a misogynistic environment in the US), all of a sudden you are perceived as potentially sexually threatening.
When you are perceived as a masculine woman (or god forbid, perceived as fully transmasculine or a trans man) you are often perceived as a “woman who wants to be a man”. And a lot of people assume that if you are a “woman who wants to be a man”, that means wanting to be like a toxically masculine cishet man, including being sexually predatory, because taking on a patriarchal sexual role is seen as the default for men (and, by extension, masculine people, because many people think masculinity = emulating patriarchal cishet manhood).
Lesbians and sapphic people who were raised as girls (or anyone perceived as such), particularly butches and anyone else raised as a girl who is perceived by others as visibly queer/GNC, do not get treated with the same grace and assumption of inherent innocence that gender conforming people raised as girls get in terms of being assumed to be only ever the victim of sexual violence and never the perpetrator.
Because we are masculine in a way that is seen as undesirable under cisheteronormativity because “women are supposed to be feminine”, it is assumed by many people that 1) we are less likely to get sexually assaulted because we are “less sexually attractive” according to current cisheteronormative beauty standards, and 2), that if we do have sexual or even just flirtatious interactions with someone who isn’t already genderfucky themself, we must be forcing, coercing, or manipulating them because, in their minds, no properly feminine womanly cis woman would ever willingly have sexual relations with some kind of a dyke wannabe-man freak. These ideas get weaponized against us. These attitudes are a combo of anti transmasculinity, transandrophobia, butchphobia, and lesbophobia- but I also want to point out how I believe that the intersection of misogyny and saneism/ableism hugely factors into this too- specifically the “crazy hysterical nonconformist manipulative aggressive bitch of a woman who uses sexuality as a weapon to bamboozle poor innocent normal people” stereotype. As a trans man with moderate to severe mental illness and chronic physical illness, this is a bigoted trope I am very familiar with having applied to me in various different contexts.
(CW for COCSA for this part, skip if you don’t wanna read about that) There was a gender conforming cishet girl I was friends with who bullied and sexually abused me repeatedly as a kid, maybe when I was 10 or so (and at the time, very closeted but still already very much percieved by both children and adults as a Deviant Failed Girl)- and funnily enough, her parents didn’t want us to be in a room with the door closed together- because they thought that I would do sexually inappropriate things to her, because I was a gender nonconforming “girl”. They would randomly walk in the room during our sleepovers to try to catch me doing something sexually inappropriate to her, and generally antagonize me in other similar ways based on the idea that I was a potential threat to their daughter’s sexual purity. They never once considered that she might be the one doing those types of things to me, despite the fact that she was exclusively the one initiating (non consensual) sexual contact with me. The one time she ever got caught by her parents in the act of sexually abusing me, even though I was coerced to do things to sexually humiliate myself entirely against my will, I was the one who got blamed for it and got in trouble with her family, while she was seen as the victim in this situation somehow of my “corruption”- like the assumption was that somehow I must have manipulated her into sexually abusing me? I don’t want to go into more detail about this right now but I hope what I was able to say can serve as an example for the type of treatment that butch girls/“girls” experience.
I genuinely hope this explanation helps you (and anyone else reading) understand what I’m getting at better. I have been pretty low on energy lately (so no guarantees) due to going through some personal shit, but if there’s anything here you want me to elaborate on I will (hopefully) try.