I've heard it suggested that before the ~1990s, nobody considered gay and trans to be separate issues — if you were a trans woman, you were presumed to be attracted to men. (I can't find the reference to this, bah)

This spells it out a different way... that if you were transgender, you were assumed to be straight... and that if you came out as gay, the trans community (and gatekeepers) shunned you.