Where did Dumbledore is Gay come from???

the script writer for half-blood prince wanted to have a scene where dumbledore recalls an attraction to a woman but JK Rowling crossed it out and wrote "Dumbledore is Gay". She also told a fan once and she thought the fan "was going to hit her"

I thought it was because that video
Harry Potter Puppet Pals Ron's Disease

He had a relationship with Gellert Grindlewald that can be described as 'romantic'. There's nothing in the literature that it became physical. Personally, I wasn't surprised by the revelation, and it really doesn't matter. A person is not defined by who they're attracted to.

J.K. said it in an interview.

JK Rowling herself. she said in an interview!

link