I think Rowling kept Dumbledore's sexuality quiet until now because there would have been a backlash from the Christian Right if she would have outed him earlier, you know, book burnings, calls for it to be withdrawn from schools....."J K Rowling wants to turn our little boys into homosexuals and god hates fags" ... you could write the script

Oh yeah, they did the book burning and banning even when they thought he was straight.
Of course blind Freddy could have told you Dumbledore was gay, but the the loony religious right is so IQ-challenged they would never have picked up on it
