Voted "Yes", it is a form of transphobia and bigotry.
BUT the key thing here is what you decide to do about it. This doesn't mean you "should" go out with someone you don't want to, but accepting that our preferences are formed and shaped by the discriminatory prejudices of the society we live in gives us an oppurtunity to reconsider our feelings and to explore them. It's not often I admit it, but I consider myself a "sexual racist" in that many of my sexual fantasies do conform to racist sterotypes. [edit: And lets be honest for a second, isn't sex the area of human activity that makes us most honest about our darkest and repressed drives? acceptence is a good thing in that sense because it means you accept yourself as the less than perfect individual we all think we are. if your going to be bad, the bedroom is the best place to do it (consensually).
]. I've had the rather difficult experience of questioning whether my first bisexual crush (unrequited before you ask) was down to racist expectations of black male hypersexuality rather than who he was as a person. either way, I loved him very much and I did make the effort to respect him for who he was and that is what counts.
it is a mistake to treat racist, sexist, transphoic, etc "preferences" as a sin to be punished as ultimately we should act based on our attractions and enjoy them. it isn't healthy to think you should punish yourself for such things as our emotions and fantasies are they often much more honest than our thoughts. you can feel uncomfortable about someone for being part of "them" but you still have the capacity to reconsider whether that is really an accurate response to the situation. there is
some degree of choice involved but not a great deal I have to admit because of how deep in the unconscious these behaviours are. Rather than thinking "that's wrong" and trying to punish myself for something that I didn't chose to be, I make the effort to reconsider those fanatasies in a new light and be open to re-thinking my "preferences". If some part of you crosses the divide and stop seeing another person as an object and begins to empathise with what it must be like to be treated that way, its a step in the right direction. we aren't going to treat everyone perfectly equally but we can recognise the role of discriminatory ideologies have in our relationships and seek to change them.