Too true! The only biologically female companion that the player can't bang is the companion that the player can choose to avoid recruiting.
I doubt we'll ever see an exclusively gay female companion. Lady companions are, by all evidence to date, designed to be accessible to all.
and what do you think about the male version, oh wise one?
btw, I was under the impression that they got rid of the choice to .not. recruit someone... back in beta *scratches head*