Why does it even matter?  If she released this information to rile up the Christian Right (who, let's face it, were never big Harry Potter fans to begin with) then any success she had in doing so only makes the Christian Right look petty and reactionary.

Why is it a problem to learn, as an incidental biographical detail, that a fictional character who exemplifies various noble virtues was conceived of by the author as being homosexual?  The reaction seems disproportionate, given that the most anyone could take from this is that Homosexuals are sometimes good people.  Is anyone with half a brain denying this?

Even if you think homosexuality is wrong, i still dont see the problem.  Gandalf was a smoker.  So what?

It isn't possible to judge her purpose...

...unless it is by the unreliable method of appealing to our own preconceived ideas on the subject.  Notice i said "If" before.  i have no idea what her purpose was, nor do i particularly care.  If it was bait, a lot of people have been fooled by their prejudices into taking it.  If it wasn't, then the same people look foolish.

He's an old man in the books.  Sexuality is expressed in more subtle ways as we get older, and not in ways which would be relevant to a mentor-student relationship.  Do you think you would know if your favourite high-school teacher was gay?

And maybe that's what it did.  The issue only came up in response to questioning afterwards, so i would say that she left it mostly to the imagination.  It certainly contradicts nothing about what else we already knew about the character, so there's no reason to think that she didn't have it in mind all the time.  It just wasn't relevant in the novels.

Maybe professor McGonagall is a closet lesbian.  Maybe Snape is a marxist.  Maybe Hagrid is an Anarcho-syndicalist transsexual.  The major point here is why do you care?

That would actively contradict things that are already known about the character.  It would also be less plausible.  As it is, it is entirely likely (statistically) that some of the Harry Potter characters, were they real, would be gay, so this revelation is neither outside the bounds of probability nor inconsistent with the story.  It rather seems that only people with an anti-homosexual agenda have objected.  i doubt that we'd be hearing all these complaints about provocative additional biographical details if Rowling had mentioned that Dumbledore was vegetarian.

The first study showing a link between smoking and lung cancer was published in 1943.  Bad timing by the German scientists in question, and their research was almost totally ignored at the time, so you're basically right.  An interesting parallel there - the dangers of smoking were relatively unknown when Tolkein published, and the dangers of Homosexuality had been wholly debunked by the time Rowling did.  And yet still with the objections....

That assumes the individual in question is in some form of relationship, not the case with Dumbledore.

i'm not sure that JK Rowling is obliged to operate on the basis of your personal desire for homosexuality to be invisible unless it conforms to your prejudices.  The personal relationships or preferences of the older characters in the books are rarely discussed explicitly, but that doesn't mean that the author cannot have any opinion on them.

You're a fan of the book?  i know that SJ has blogged in the past that Harry Potter contains more Christian themes than those who reject it as evil witchcraft inspiring literature realise.  No wonder he's ticked off. 

i have no problem with fans of the book discussing any aspect of the creative process, i just think that by homing in on this particular issue like a heat-seeker people actually expose motivations of the non-pure-academic-curiosity type.  More the political activist type.  It seems disingenuous to claim the former.

i have no objection to eye-brow raising.  Actually, i also have no objection per se to this kind of politically-motivated-disguised-as-dispassionate-inquiry either, i just think it reveals a bias if Dumbledore's "outing" is the only subject discussed.

You are endorsing the same kind of narrow-minded adherence to the simplest of statistical trends which could easily have been used in the past to make arguments about the "dangers" of being black.

In fact, it still could.  Does the fact that black people are disproportionately represented in the prison system necessarily mean that they are disproportionately criminal in their nature?  Or might there be some other factors involved which would render the most simplistic conclusion invalid.  People who make this kind of argument are only showing their prejudices more plainly.