So here's what JKR has recently said about Dumbledore, getting more into his sexuality:
"I had always seen Dumbledore as gay, but in a sense that's not a big deal. The book wasn't about Dumbledore being gay. It was just that from the outset obviously I knew he had this big, hidden secret, and that he flirted with the idea of exactly what Voldemort goes on to do, he flirted with the idea of racial domination, that he was going to subjugate the Muggles. So that was Dumbledore's big secret.
Why did he flirt with that?" she asks. "He's an innately good man, what would make him do that. I didn’t even think it through that way, it just seemed to come to me, I thought 'I know why he did it, he fell in love.' And whether they physically consummated this infatuation or not is not the issue. The issue is love. It's not about sex. So that's what I knew about Dumbledore. And it's relevant only in so much as he fell in love and was made an utter fool of by love. He lost his moral compass completely when he fell in love and I think subsequently became very mistrusting of his own judgment in those matters so became quite asexual. He led a celibate and bookish life."
Clearly some people didn't see it that way. How does she react to those who disagree with a homosexual character in a children's novel? "So what?" she retorts immediately "It is a very interesting question because I think homophobia is a fear of people loving, more than it is of the sexual act. There seems to be an innate distaste for the love involved, which I find absolutely extraordinary. There were people who thought, well why haven't we seen Dumbledore's angst about being gay?" Rowling is clearly amused by this and rightly so. "Where was that going to come in? And then the other thing was-and I had letters saying this-that, as a gay man, he would never be safe to teach in a school."
So this is how a lot of this doesn't fit with my own interpretation. EtA: It's been pointed out to me that this line caused some confusion--I'm not disagreeing with "He is a character that just happens to be gay" or that Rowling concurs with that idea. I'm saying I had a different interpretation of why he'd be attracted to Grindelwald's ideas based on what I read in canon. So I took out the last paragraph of the quote, which wasn't really needed.
As an aside, if Dumbledore is celibate and maybe never consummated his relationship with the evil Gellert, that actually *is* the point according to many people, because as many will explain, the problem isn't having "gay feelings." The problem isn't love. The problem is you're having sex with someone of your gender. If you don't "choose to sin" by actually having sex, you're not entering into that wicked "lifestyle" they don't like. Dumbledore's done just what a gay man is supposed to do according to many anti-gay opinions. It actually is about sex: a-sexual gay men are always more acceptable than sexual ones.
But the weirdest thing here to me is in the second paragraph, where Dumbledore is apparently an "innately good man" who only flirted with essentially *being a Nazi* because he became a "fool for love." This is bizarre to me because frankly, I don't have any trouble trying to figure out why Dumbledore would have flirted with taking over Muggles. This is a guy who's constantly manipulating everyone, thinks he's smarter than everyone else, treats them as pawns that are morally inferior to himself...why on earth would it be hard to imagine him deciding to dominate Muggles "for the greater good?" Of course he would think the answer was having the right people in charge.
But it's disappointing in a familiar way, the way that once again something that seems to be an inherent flaw in a character on the good side that totally mirrors the evil they're fighting, the author wants to make it the fault of the evil characters. Dumbledore's "love" says no more about him than Harry's Voldemort sliver. It takes the blame for unacceptable behavior. Suddenly Dumbledore's real racist tendencies (unlike Snape's) don't come down to his own desires or his own personality. He's acting unlike himself because he's been vaguely "made a fool by love." And love, as we know, is just some random thing that hits you like Cupid's arrow or the author's pen. It's not even presented as something you can analyze in terms of...well, why exactly did you find Hitler so attractive? Doesn't that say something about what calls to you? (Without even getting into the fact that this most poisonous loves is the one gay one.)
The author here seems to be saying that she needed or wanted Dumbledore to have flirted with all of this, but then needn't to figure out why he would do it. Rather than looking at the character and saying, "Ah, I can totally see how this guy would be attracted to this." Instead it "just came to her" that "he fell in love." It's about someone else, something beyond his control. It's about this other person. He "lost" his moral compass because he fell in love (which was beyond his control to begin with)--his compass never truly pointed to this.
Dumbledore himself even agrees! He becomes mistrustful not of his moral compass, not of his own abilities to know right from wrong. No, he becomes asexual, deducing that the problem is that he needs to keep himself pure from others so that he can always be sure he's relying on his own "innately good" moral sense. He's got more reason to keep secrets; he doesn't decide he maybe ought to keep other people around to make sure he's not going down the bad path again. Listening to other people can only be trouble.
Well done, Dumbledore! Way to be morally superior about your own past as a wannabe Nazi!