As a general matter, I'm with you as far as JKR's extracanonical comments are concerned. I was annoyed, for example, by JKR's need to explain Sirius' character on her website, or her ever-changing views on certain points, like Ron's job.

This was different, though, because the revelation that Dumbledore was gay, to my mind, fits seamlessly with canon. JKR did write him as a gay character, and I can embrace this revelation, unlike so many others.

Unfortunately, though, it seems to mean that in the WW gays are still more or less in the closet, and that saddens me.