They dislike chasers because they're not "validating". To troons, there is nothing that validates their true and honest womanhood more than a straight guy or lesbian woman shacking up with them. Of course, "straight" guys that date troons are just repressed bisexuals, and "lesbian" women who date troons are just straight girls who want woke points.
Chasers firmly acknowledge troons for what they are physically-- men in dresses with tiny horse-pill tits-- because they have fetishes for it. They specifically like troons for the things that make them demonstrably not women, which offends troons to no end. When inevitably ends up happening is troons either dating each other or troons dating chasers who lie about not being chasers. Or waiting until after they've married and impregnated some hapless straight women to troon out.
The case is similar for FtM troons, particularly ones that seek out gay men. Gay men are even more open about rejecting troons than lesbians are, you just don't hear about it because FtMs are less common and less visible than their MtF counterparts. Straight men, on the other hand, are happy to lie to FtM troons about being gay for an easy lay. I recall seeing a screenshot from some PUA forum where guys were talking about how they'd seek out fakebois at anime cons, lie about being gay, and get free anal because the troons were under the delusion that a gay guy was "validating" them and they were having uwu yaoi sex. I've seen a handful of gay guys solicit sex from FtMs, but it's usually because they don't understand what's going on and think the person has a penis and/or they're looking to experiment.
There's a fantastic Tunglr blog where some asshurt fakeboi posts all of the rejections and questions she gets from men on Grindr, and though I think she intended to prove how evil and insensitive gay men are, all it proves is that people with vaginas don't belong on Grindr. Obviously. The sad thing is that a lot of the messages she posts are literally just gay guys adulating her for being "brave," but for some reason she takes that as an insult and feels the need to post it on her blog. The rest of the messages are just men being horny, which is pretty normal on Grindr, because gay men don't get angry and uppity when they get dick pics or blunt requests for sex like women do. Y'know, because they're men. This fakeboi getting offended is all the more proof she's a woman and shouldn't be there.
