Not to be vaguely nasty like the above anon, but yes. It's exactly that. I find vaginas nasty because I have one and I am only interested in dicks touching if we are talking about smut.
I haven't read a lot of fics with trans characters but some fics that I've read were indeed quite stereotypically het. (And some were blatant suffering porn that's another... thing)
But I know people who are strongly into trans!porn and like to read about trans characters so surely you must have your readers even if it's not wider audience.