Homosexual people have existed since the dawn of time so they'll also exist in the future.
The absence of homosexual characters doesn't imply that there are supposed to be none. I am German and the only Germans I have ever seen in Trek were nazis ... but this doesn't mean that Germans don't go into space and I couldn't care less about their presence or absence. To be frank I don't care about the absence of presence of LGBT folks (let's not forget transsexual people who have a much harder time than gay or bisexual folks) in Trek either whereas I enjoyed the few episodes that dealt with sexual identity very much.
Let me use your Abrams quote to point out why I am against these representation games. The last Trek movie was probably the most unenlightened Trek story in years and the folks at the helm make it crystal clear that they don't care about the general principles of Trek at all.
Suppose there will be a gay character in the next movie such that everybody can claim that JJA et al are so progessive ... while they are in fact not giving a damn about Roddenberry's vision at all. You also have this a lot in politics, gay right-wingers like Fortuyn or Haider can pretend to be liberal and open and so on while they are in fact the very opposite.
To prevent any misunderstandings, I am not against the presence of homosexual characters in Trek, I merely like to emphasize the importance of a holistic perspective. At least for me Trek doesn't automatically become good when discriminated folks are represented; it takes more than that.