Let’s get this out of the way: I really, honestly, truly do not give a good goddamn if Dumbledore is gay. He’s a fictional character, the author is getting a little too freakily obsessive over her characters, and it doesn’t affect me one way or the other how the character swings. So Rowling says he’s gay. Eh. Move on.
It only gets interesting when a certain ID proponent who has weebled on about how delightfully Christian the Harry Potter books are hears that her imaginary character imaginarily experiences arousal over another imaginary character who is, imaginarily, of the same sex as he is. This prompts an immediate long outburst declaring that Dumbledore is NOT Gay! That would conflict with his perception that the books are Christian allegory, and as everyone knows, no true Christian could be gay, just as there are no homosexuals anywhere in Iran.
It’s more fuss over nothing. Dumbledore could have been written up as a flaming ponce who hung out in the Hogsmeade Bathhouse every weekend and did drag cabaret for fun, and you could still read Christian themes into the book, no problem. Of course, the Christian verisimilitude would have been enhanced if Dumbledore had also called the boys in to his office for regular ‘discipline’ sessions of a nature best described in off-canon fanfic, but he seems to have been free of that pedophilic poison that we find rife in ecclesiastical organizations.