I live in Alabama, and it's a mixed bag here. I'm straight, but I've always had gay/lesbian friends, and would occasionally go with them to the local gay clubs. It never really bothered me, it was just like any other club, just with lots of same-sex flirting.
I was however, dubbed a "******" by a kid in highschool, for no reason I can fathom other than he randomly selected me to bully, and it stuck for years. He and his friends openly mocking me for no reason other than him deciding to mock me for being gay. Which always baffled/amused me since I wasn't. Personally I think he was just jealous that I had lots of female friends, and would sit with them at lunch, something that baffled all my male friends who didn't understand how I pulled it off.
As to the core question, there are several people here who are openly anti-gay, and where I work, I will sometimes hear customers talking about "The Bible says Adam and Eve, not Adam and Steve!" and other such stupid shit. But they are the minority, the openly anti-gay group. Of course I have no idea how many are quietly anti-gay, as they are obviously being quiet about it, but I don't see much in the way of blatant anti-gay sentiment here.
My circle of friends over the years has almost always included a gay friend/coworker/roleplaying buddy, and it's never been an issue with us. I'll ask him genuine questions about his sexuality, and other things simply to have a discussion about it, and the topic is perfectly comfortable. We'll tease each other, and jokingly flirt around the gaming table, if something comes up that could be given a humorous gay slant or riff. But for the most part, it's just a regular part of things.
Now, that being said, I don't see many openly gay people around here. So if I had to guess there is some level of "keep on the down low" vibe, just to be safe, but I don't know, that's just my observation.
I think it mostly depends on the group of people you're talking about, no matter where you live.