It's not that having a preference is problematic. There's a huge difference between trans/disabled chasing and being open to dating trans and people with disabilities. Chasing is a sort of fetishization mixed in with some dumb ideas about what masculinity is. Whereas a preference in dating is more along the lines of 'i like you and that part of you, you like me, let's do things together that we like.' The difference is about respect and equality in the relationship.
I don't know what your definition of "chasing" is, but whatever it may be it seems to be independent of the group that's being "chased".
So in that case you could say "chasing" is bad while a preference is not, completely regardless of whether you're talking about trans people, disabled people or any other group.
I feel like im about to get screamed out of town for this, but it's an honest question in good faith so im gonna ask it... What's the difference between trans chasers and, for instance, a straight dude "chasing" cis women?
It seems like someone being attracted to the combination of your genital configuration and your gender preference/presentation is what you want right?