It's Jane who has made a link between Frankenstein's monster, a fake pseudo-human made of a mash-up of dead bits who is psychologically tormented by its own existence, and trans people. I would have thought that was massively transphobic!
I also can't see how the monster is in any way like Norman Bates or Buffalo Bill. They reflect what has been well-known in psychology and criminology for a long time, that mentally unwell male murderers of women have high rates of cross-dressing. (In a real-life case I slightly knew the victim of, in the 90s, the killer then put on the victim's clothes.) It's a thing and related to the fact that sexual fetishes often come in groups and tend to escalate.
Frankenstein's monster is nothing like that, it isn't claiming to be a different sex or displaying a fetish and it it isn't evil. Though as we can see from Jane's confusion about who Frankestein is, Jane hasn't read the book.