If you want people to be treated equally, wouldn't you want their existence to be justified?
It's difficult to think of a PC analogy here, so maybe... super villain mind control device strapped to someone's head. Provably unjustified behaviors due to the mind control device implies the ethical thing to do is try to remove the device. Treating someone normally implies an implicit belief that they're normal. Sound biological evidence that being queer is just how some people are feels like the best way to reinforce that belief and remove requirements for heteronormativity.
It's difficult to think of a PC analogy here, so maybe... super villain mind control device strapped to someone's head. Provably unjustified behaviors due to the mind control device implies the ethical thing to do is try to remove the device. Treating someone normally implies an implicit belief that they're normal. Sound biological evidence that being queer is just how some people are feels like the best way to reinforce that belief and remove requirements for heteronormativity.