Sulu is/isn't gay has no bearing on me not wanting to see it... I don't want to see it because I saw the "we swear it's not Khan" one and that movie was so bad (so bad I can't even recall the name and won't even bother looking for it), I pretty much swore off seeing any more of these New Trek movies.
Just to be clear - I could care less if any of the characters are gay or not. I'll even go so far as to say they should have a gay character given how Roddenberry was deliberately inclusive of both genders and many races in the original series. Even if its not necessary for the story, I can see where this might have been included with the original material back in the day.
I just don't want to support the movie for using the gay card as PR when the actor they were supposedly trying to support asked them to not to go this route. I actually kind of like the new Star Trek stuff, but am already sensitive to this stuff with Marvel revamping all their characters lately in much the same vein. If you really want to include minorities in your stories to make your cast more representative, then do it organically with new characters and do it for a reason other than building up hype and controversy.