Dunno why it bothers some people to hear that Dumbledore is gay. I also don't think it was for publicity's sake. As an author of a very involved series I would imagine that you would get very attatched to characters and make up backstories for them.
Stephen Fry's message is so true. People that are homosexual are not trying to make others homosexual. What they want is to be accepted, just like everyone else. However, most homophobes on the other hand are trying to place their negative and unfair beliefs on others to make them also homophobic. Which is demeaning and inconsiderate.