Harry Potter: Full of Homosexuals, Apparently

I'm not sure why anyone really cares that a character in Harry Potter is gay but it's getting lots of media attention. What I find interesting the character somehow exists outside of the books (or the movies for that matter) and it's up to the author to tell us what the character's sexual orientation is.

I admit I haven't read the book (I read the first 50 pages of the first book and found it so awful I couldn't continue, thinking that I'd just see the movie. I did, and I'm still undecided which was worse) so perhaps this character's sexual orientation is a crucial plot element, though I doubt it. Rowling mentions that she had to pass a note to one of the movie's script writers that this character was actually gay, which says to me that it's not clear in the books that he is. (Assuming that the script writer would have studied the books on a level the casual reader hasn't.)


The question is then -- can a character exist beyond the text? You can give the author a certain amount of leeway in these matters, but I would argue that if it's not clear (at least ambiguously) in the text than it isn't 'true' (in so much that something in a book about a boy wizard is 'true').
Any interpretation has to be based on some evidence or it's just making things up -- I can read Harry Potter and say that he's actually a cyborg sent from the future to kill a woman who will give birth to the leader of the human rebellion against the machine overlords -- it's just not mentioned.