I think quitting over something like that is really over reacting. Your sexuality should have no relevance in your workplace.
I'm gay, I work for a company with extremely homophobic people. Heck, today someone sarcastically told me that me and my manager would make a cute couple if we were gay. I just laughed them off, and turned the joke on them. If i felt the need to get my knickers in a twist about it, i would only have handed them serious ammunition to make my life miserable.
Take it easy. If your boss asks who owns the homosexual teas, tell him you're sure he was the one who bought them last week, make sure the rest of the office hears you, he'll laugh, you'll laugh, end of story.