Eh, I wouldn't let it get to you. I'd be a bit uncomfortable too.
And I'd like to point out, one of my oldest friends is gay. I've got absolutely nothing against him. I've got no secret fears that he's harboring attraction for me. He's a great dude, always reliable, and quick to lend a helping hand whenever you need him. We frequently hang out at events my more 'macho' friends don't quite get: theater, band, opera.
I don't know many straight guys who would willingly sit through a musical either. So it's good to have a friend who'll make me feel less out of place.
But you couldn't -pay- me to live in a 'suite' full of people who have such fundamentally different lifestyles from my own. It would be as bad as if I tried to drag one of my buddies from the shop to go see 'Phantom of the Opera'. Everyone would just feel awkward and nervous and out of place.
Every day. Until such time as I moved.
It's one thing to be friends, to hang out, or to socialize with people. It's another to live with them. Now, I'm assuming this guy didn't know you. So I'm operating under the assumption that I have to -assume- what the gay neighbors and bi-sexual roommate would be like.
My 'assumption' would instinctively be that there are quite a number of differences, up to and including sexual preference. And that would make me nervous. Not only on the level of 'what am I going to walk in on when I get home?', but also on the level of 'do I really want to have to be careful how I speak every day to avoid offending someone?'
It's rough. It's hard to always be socially mindful. That's why we instinctively group into groups of like-minded folks. It's more comfortable to deal with people who behave and react in ways which you can understand and predict.
But look.
My guess is, it would just have been terribly awkward and uncomfortable for the guy. He was probably being very honest when he said he didn't have a problem with you on any kind of a personal level... and that he didn't feel comfortable trying to live with someone who is bi-sexual, and having gay neighbors, and never really knowing how to act and behave.
And that's nothing to be offended about. It's a symptom of unfamiliarity and uncertainty.
So I come back to my point.
If it's bothering you, I wouldn't let it. And if it's not bothering you, then all the more power to you. Because it's awkward all the way around, when two people don't really know how to interact with each other.