To me, it's been more interesting to see the reaction to Rowling's decision to share information about her characters which wasn't in the books. The Dumbledore revelation is hardly the first time she's done this. She's talked about Neville's love life, Ron helping out at the joke shop, and so on. Some people feel it would have been better had these revelations appeared in the book. (I tend to agree.)
John Scalzi points to an essay by Edward Rothstein who goes even further. He states, in part, "[I]t is possible that Ms. Rowling may be mistaken about her own character. She may have invented Hogwarts and all the wizards within it ... but there seems to be no compelling reason within the books for her after-the-fact assertion."
Scalzi disagrees, stating, "Sure there is: Because he is. Because the author made him that way. Whether or not anyone but the author knew about it up to last week simply doesn’t matter ... Rothstein seems to be falling into the trap of assuming that everything that goes into a character shows up on the page."
Neil Gaiman appears to support Scalzi ... or maybe it's the other way around. Anyway, Gaiman says, "You always wind up knowing more about your characters than you can get onto the page. Pages are finite, and the story isn't about giving you all the information about everyone in it any more than life is."
All three individuals go into a lot more depth and detail, of course. And as an author, my gut reaction is to agree with Scalzi and Gaiman. Just because I never stated who Jig's parents were doesn't mean I don't know. It only means that information didn't matter in the first two books. But these are my characters, and what I say goes.
But my experience with literary criticism nags at me until I find myself doing the unthinkable. I'm going to disagree with Scalzi and Gaiman. Or maybe not ... in that same post, Gaiman also says, "it's never really real until it hits the page, because the process of writing is also a process of discovery."
Dumbledore's sexuality isn't explicitly spelled out in the books. That means we can still argue about it. Rowling's revelation can inform that argument, but it doesn't end it. Because once the books are done and published, authorial intent becomes irrelevant. The story you intended to tell may not match up with the story that was published. (How many of us, as writers, have watched a story which was beautiful and amazing in our heads turn into something much less shiny when we actually wrote it out?)
Let me jump to another example for a moment. In LA Weekly, Ray Bradbury talks about Farenheit 451. "Fahrenheit 451 is not, he says firmly, a story about government censorship."
Does Bradbury saying so make it true? I don't believe it does. Particularly if you read what Bradbury wrote many years ago in a 1979 edition of the book. "Students, reading the novel which, after all, deals with the censorship and book-burning in the future, wrote to tell me of this exquisite irony."
If both of these quotes are accurate, and I believe they are, that would imply that the author is not a reliable source of information about his (or her) own books.
Rowling claims that Dumbledore is gay. I believe her. Not because the author said so, but because my reading of the text supports that interpretation. Literary criticism is a big, ongoing argument, and a strong argument can be made to support Rowling's claim*. If Rowling did choose to release another Harry Potter book (and I don't believe she will), and if in that book she showed us Dumbledore having a relationship with another man, that would put an end to most of the arguments. For the purpose of understanding and interpreting a text, once something is in that text, it's real.
I appreciate hearing Rowling's thoughts on her characters and their fates. Her interviews have helped inform my reading of the books. But they don't dictate how I read. Nor should they. Indeed, those of you who have been following Rowling's discussions closely might note that she initially didn't think about Neville and Luna getting together, but once it was brought up, she began to come around to the idea.
So there you have it. My two cents on authorial intent and the information that doesn't make it into the books. Authors always know more about their characters than they put on the page, but until it appears on the page, it's not real.
Debate and disagreement are more than welcome, of course.
Also, Smudge the fire-spider is gay.
*This led me to an interesting tangent. IMHO, good fan-fiction draws on plausible interpretations of the text, continuing the story based on the fan-fic author's reading of the text. The more the fan-fic author can support their interpretation, the better the resulting fic will be. Which suggests that fan-fiction and literary criticism have an awful lot in common...