Are they cis guys who are attracted to trans women but don't know how to process that in healthy ways so it comes out in transphobia? Are they just transphobes and they get their jollies out of being straight up sicko creeps? Or something else entirely? I'm just curious as to what makes them tick.
Cissie here, but I always see it explained mainly as #2 there.
#2 would also be consistent with other especially reactionary fetishes. For example, it has long been recorded that a disproportionate number of overt white supremacist men enjoy porn that is oriented around a black man having sex with (or raping) a white woman, sometimes in the context of that woman having a white male partner already. There is a lot to be said about this if one can stomach to dwell on it, but the short version is that they seem to be sublimating the "racial anxiety" that their ideology has caused them, turning it into a source of sexual pleasure in order to cope with it.
I would suspect from testimony like appears in this thread that the chaser's fetish is driven by seeing trans people as subhuman, and thus in some manner either the chaser is 1) "debasing" themselves, a sublimation of anxiety into sexual excitement like the racial example or 2) seeking to "dominate" the "lesser" being that is their trans victim, hence the frequency of abuse.
Anyway, that's what it seems like from the outside. I of course welcome correction from people who might have experiences that disagree with me.
In 1960s-70s Israel, Nazi porn was a big deal. From my study of historical sexuality, it doesn't really matter what it is, as long as it is forbidden. Some of us humans just love love love anything, as long as it's taboo. The really sick people come from libertines who don't have any taboos. They have to get into the seriously abusive and even murderous to get their rocks off.
There is a sort of pipeline for the porn that leads to this behavior. Shock humor -> Habituation -> Testing the Waters -> Ironic Acceptance -> Negotiating Unironic Acceptance -> Embracing Fetishization. There's stuff out there mostly meant to troll people not into this stuff, and then catch and subsume them into their weird little community so more content gets reposted or commissioned.
Weird that they enforce the cycle of abuse and trauma by checks notes showing each other trans bodies