I think it would be more acceptable to people if there was a tangible difference beyond not having kids. Having homophobic dwarves that get unhappy thoughts from seeing Urist McClothier in his leather thong would be neat, in a similar manner to the dwarves who hate nobles. Perhaps gay dwarves would only remain 'lovers' until a sympathizing dwarf was elected mayor, after which point they could marry, or the opposite would be true if a homophobic dwarf was elected... stuff like that. Most of the traits are intended to serve some purpose in the future, if they don't already, and the addition of more sounds totally fine, since this is really just a character trait. The idea of moral conflict is rather silly, since this game is played from the perspective of an amoral overseer who is presented with the various civilization ethics with more or less objectivity. We're told dwarves don't like eating elves, so we deal with it. Would we let them if they could? As sure as we let them eat kittens and puppies.
Dealing with ethics really should be more dynamic than it is now, and this would be a good start. More productive than debating its 'controversy' or whatever would be to discuss the effects it would have on the game.