The way I see it, it is what you want it to be. I'm not one who believes that the author's/song writer's intentions should automatically take priority over other interpretations. If you believe that it a gay anthem, and are able to justify it as such, then I don't see the problem with you believing what you want to believe.
But you need to be able to justify it. While I don't agree with it, I can understand why some people might interpret WATC to be a gay pride anthem. However I think it would be foolish to interpret it be Freddie's views on the Middle Eastern peace process, or Garry Sobers's place in cricket or on whether Gone with the Wind was overrated.