I don't think it happens in just the gay community - I think it's a pretty universal response to rejection. Just look at how people react on American Idol when they're rejected!
I've heard some pretty nasty rumors about myself over the years, and you have to just shrug them off. I remind myself that the people who know me and love me (and accept me for all of my faults) know the rumors aren't true (except for the ones that are :twisted
I've also seen it in the business world, too, when someone makes a bad mistake or really misses a deadline. Somehow it's not their fault and they make up stuff about other people to take the blame off of themselves.
Just remember what Oscar Wilde said: “The only thing worse than being talked about is not being talked about.”