A permutation of this transphobic claim: Any pure sexual orientation — straight, gay, maybe bi — involves cis people being attracted to each other. Only cis people. A cis person who's truly in touch with their sexual orientation would never date a trans person, you see. Sexual orientation depends on clear ideas of maleness and femaleness, manhood and womanhood. If you wreck gender, you wreck sexual orientation. On this view, trans people who want to date cis people are attacking the reality and/or destroying the concept of sexual orientation. We're spoiling it for cis people. Since trans people contaminate the purity of all sexual orientations, and since gay is one sexual orientation, trans people attack the coherence of gayness and are therefore inherently homophobic. So, if you don't want to be homophobic toward cis gays, you should reject the Very Terrible No-Good trans people (especially those who presume to date cis people). QED.