Didn't kill him BECAUSE he was gay, or you'd have a point. Even better, their sexuality wasn't a plot point AT ALL (I consider this progress in the right direction). No one commented on it, they didn't have to prance around and act flamboyant, it wasn't a factor. they were just another couple, and it was left at that.
In fact, of the 3 couplings presented so far (Captain/Admiral, Burnham/Tyler, Doc/Stamets) (I'm terrible at their names, btw), this is the only relationship that was presented as normal or healthy in any way. that IS them being treated as normal and accepted from what I can see. And the death (if permanent) was because the audience would care, not getting rid of the token gay or fixing a mistake. killing someone you care about to raise the stakes. Sexuality had nothing to do with it. what was the sexual orientation of the guy Burnham killed in the elevator? Also not a factor.
Sorry if you're trigged by that, but not sure how else to present it. If you want the toy included in the toybox, can't also insist that it stays in its packaging and the writers can't play with it. if you want a token gay character to just sit in the background and never have anything bad happen, to each his own, but I'd rather they get into the fray with everyone else, and both good and bad things happen. Just like any other character where sexuality isn't important to the plot. Otherwise, you get your token gay, but he doesn't matter and no one cares.
Cultcross, what IS the number of episodes that he would have had to be in before it would be acceptable to kill him (or have anything bad happen)? You're implying it was bad because it was season 1, but is season 2 ok? Season 4? 7 seasons and a movie? Seems a silly and arbitrary point. Plus, if you're worried that the gay character got killed after not being in Trek for 50 years, may want to remind yourself that there's still another one in the senior staff and the credit run. Didn't just introduce a gay character to check the box and then kill them. One DID lose a love interest, though, which usually results in more screen/story time for the survivor of those sorts of events...