ETA from conversation elsewhere with
I don't know why Harry Potter is THE bestselling series of our time. I suspect none of the lit critters do either. Is it something progressive, mapping our social values onto a system even more archaic and medieval in structure than academia? Or is it something hopelessly retro, inherently sexist and aristocratic? How come it rings bells among readers in Japan and Brazil as well as in Rowling's native UK and places colonized by the British? Why are these children's books being read by adults? I think it's going to take a generation and a lot of surveys before anyone can really approach those questions -- if it were something so simple as marketing or packaging, though, some publisher would have found a way, if not to replicate the success, then at least to approach it, I think.
I don't recall anyone in HP saying explicitly, "Harry is in an interracial relationship with Cho" or "Ginny is in an interracial relationship with Dean." We just saw kids dating, whose ethnic backgrounds we happened to know, if we thought about it. So I really would not have expected anyone to say, "Dumbledore dated men!" if the idea is that these things are supposed to be completely unremarkable. Sure, I think it would have been useful if it were more explicit in the text, but Rowling may believe that because she wrote Dumbledore dressed in flaming purple and never marrying, we'd all guess. Maybe she was afraid of further stereotyping...maybe she thought her stereotypes in this case were screamingly obvious. I am inclined to believe that her explicit outing of the character only after publication is clumsiness on her part, like so many things that irritate me in the series, rather than not wanting to compromise sales.
If it looked like she was taking on homosexuality as an issue, it would be the single social issue we could actually point to in this series that was approached so directly. Personally, I wish the wizards were more concerned with healing the environment the Muggles are destroying and things like that, but we see real-world politics and social developments from a great remove. Which is probably a huge part of the appeal of HP to readers across the spectrum. And as a result, I don't think these books will age as badly as a lot of children's literature. Maybe that's pessimistic on my part, because I'm not expecting so much social progress that the predominantly white heterosexual male heroes will look anachronistic.
Rowling may well have started out intending to make Dumbledore more explicitly gay in a later book, but at some point I think she decided she wanted to be writing not just bestsellers but children's classics, and then she took the conservative route in terms of genre and character development. She said herself that she decided not to kill certain people, not to allow certain events to unfold as she originally planned. I'm not sure whether I'm sorry she decided not to deal with homosexuality directly...if she had, and it was unsubtle and seemed to be motivated by political correctness rather than character development, it would have made for yet another damn awkward spot in her writing.
So I'm ambivalent. I mean, I'd have rejoiced like hell if Dumbledore had come out in some logical, moving manner in the books. But I also think that there would be just as many people screaming that she just did it for attention and sensationalism and headlines and it's cheap and exploitative, and all the rest of the Rowling-bashing that I'm seeing right now. I expected a certain amount of that from conservative readers who didn't really want to know this about Dumbledore, but it astonishes me to hear such nastiness from pro-gay readers.