You're not intruding, sidebar says LGB men and women and our allies :) feel free to post/comment.

I'm really sorry that happened to your friend, that sounds awful. Hope she is able to find support from other friends/family who care about her. I hate to generalize about people I don't know, but if your friends call you a bigot for saying you're not attracted to someone or for not wanting to date multiple people at once, they're horrible friends.

Anyway, do these male "lesbians" have some sort of humiliation fetish?

Yes, many of them do. Ever heard of the Subreddit User-Overlap website before? You can type in the name of any subreddit and it tells you: How many times likelier than the average redditor is a person who posts/comments on this sub to also post/comment on another sub? For example, r/crossdressing is a subreddit where many MtFs (transgender-identified males, such as your friend's "trans fem enby" stalker) hang out. If you type in "crossdressing" to the site, you'll see that people on r/crossdressing are 24 times likelier than average to post/comment on r/MtF... and they're also 130 times likelier to post/comment on r/sissies, which is a humiliation porn subreddit. So, yeah, many of these men who say they are "lesbians" have a humiliation fetish.

There is also the component of: "If I can get a lesbian to date me, then that means she's convinced I'm a woman; therefore, I must be a woman!" They try to date lesbians specifically, as opposed to say bisexual women, because they see it as a form of external validation.