People are allowed to have preferences. It's probably fine to state such a preference as long as it's followed by "but it's your body and you gotta do what's best for you". If that's a dealbreaker, you can let that be known in a polite way imo. But it shouldn't be used as a threat to try to push someone not to do it.

That said, my limited experience with a chaser was one showing up at my work when I was alone (and making a weird point about it ), used their job position and my job position to get me to give them my number, proceeded to complain about trans people caring about pronouns while calling us beautiful, brought up sexual harassment he has experienced on-the-job by someone who is trans, used my number to try to invite himself to visit again, and then showed up again next time I was alone at work and forgot to lock the door and leave the lights off months later to try to "flirt" with me again and mentioned I haven't been around in months (at least this time he seemed less creepy by asking if I was into guys and seemed to drop it when I said no). But from what I've heard from others, this seems pretty normal from chaser.

My last relationship like 2 and a half years ago was with a pansexual demi-girl who supported me transitioning but would like complement how it was hot that my hands were bigger than hers, and other stuff I won't mention. She gave me insecurities that I still think about, like the hands, and wince whenever I remember the sex.

For a few reasons I have like the opposite and experience like actual fear whenever I imagine what sex would be like with a pre-op trans woman. I know people talk about how awesome T4T is, but it fills me with dread. Like you're not even safe with other trans people, they still fetishize you.