I disagree that people should be able to toggle same-gender NPC flirts on or off. Nobody is forcing players to flirt. Just don't pick options you don't like.
It's really quite simple.
Not every NPC is gonna need a flirt option and on top of that, not every NPC needs to be bi or gay. There are gonna be people out there you can't bend, no matter how much you want to. There are also going to be gay people out there that if you're playing a straight character, you won't want/need to hit on. Deal with it!
Also, I'm asking for these options both as a lgbt-identified individual and as a roleplayer. I've played Bioware games for the straight romance because I felt certain characters were straight. It's fun to pretend! Not every gay person has to want to play straight characters and vice versa. I never play male characters, but there are women out there who do really enjoy playing as men. At no point did I require the option to play as male to be toggled off. Sometimes, I play asexual characters. I just don't pick the flirts! I don't need them turned off!
Including same-gender flirts increases the options for all players, gay or straight. Increasing options does not eliminate anyone's freedom to not pursue them. The only reason people who want to play gay characters are upset by all the opposite-sex Flirts in-game is because they know that they won't encounter same-sex flirt options.
I hope all the homophobic comments on this thread are by trolls but I'm pretty used to being disappointed by humanity, so I'll live either way.