ALWAYS? Up to a point, Lord Copper. Only in the sense that it was once for all of us.
It was once just a song-contest, about the songs, and thus was gay-friendly, but also everyone else-friendly.
Now, though (at the risk of repeating myself), it's become a "gay-only" thing, mainly due to the commentators on the BBC gaying-it-up.
A classic example of how "inclusivity" becomes "exclusivity" within a very short time.