I know it's been almost a year since J.K. Rowling announced that Dumbledore was gay, but that's okay--because this post isn't really about Dumbledore, or even Rowling. Not specifically. It's about the nature of literary characters.
Dumbledore, of course, is a creature of fiction. J.K. Rowling made him up. He exists only in the pages of her novels. While many literary characters touch our hearts and minds and thus weave their way into our cultural consciousness, there is one thing they cannot do: grow outside the pages of the novels in which they are born, live, and die. As a character, he is fully formed within those pages or...he remains incomplete.
I couldn't care less what Dumbledore's sexual history is like, except for one thing: he doesn't have one. At least, not one we know anything about. And Rowling's "revelation" doesn't change that. It's a cheat. The shot at developing a character comes WHILE YOU'RE WRITING THE BOOKS, and you either take it or you don't. But if you don't, you can't make things up later.
Of course, no character's entire history can be revealed, detail by detail, in the course of a single novel--or even in a series. But the pieces that define the character are revealed through his actions, his interactions, his reactions, his backstory, the things other characters say about him. Sometimes that information is subtle and incomplete, and when a "revelation" like Rowling's makes the rounds, we readers say, "Ah, yes...THAT explains why in book three...." or "So THAT was the big secret in his past that he kept alluding to." Even those seem a little cheap to me, a kind of literary easy way out. After all, it's much simpler to announce a new detail about a character in an interview than it is to weave that characteristic or piece of history subtly into the story itself.
But even that didn't happen with Dumbledore. The announcement was "bombshell". Why? In part, perhaps, because some groups had a moral opposition to the idea of a prominent children's character being "outed", but it was more than that--it was because no one had ever suspected. I don't doubt J.K. Rowling's contention that she always thought of Dumbledore as gay, but she didn't convey that notion to her readers. Dumbledore is a man without sexual identity. Kind of rough on the guy, perhaps, but that's the way he was made. And coming back later with an "oh, and by the way..." doesn't change that.