Is this thread a hoax?
J.K. Rowling does NOT lack for attention, Dumbledore gay or not. In fact, as celebrities go, she is intensely private and avoids the spotlight. She could spend every day of the rest of her life basking in the attention of Potter fans without ever making a controversial statement.
She didn't make up this piece of information on the spot to get gasps from her audience. It is clearly detailed in the history of young Dumbledore as discovered by Harry in Book 7. That nobody used the word "gay" doesn't make it any less well planned.
And as for the poster who thinks it is "rude" of Rowling to "out" Dumbledore, I can only remind her that the professor is not a real person, but the fictional creation of Ms. Rowling.