You’re right, of course.
But I don’t think Rowland made an “announcement” as such about Dumbledore.
What happened was that the director of one of the movies had Dumbledore saying something indicative of a love or an attraction for a woman (don’t remember what) and she said, ‘oh, no, Dumbledore is gay.’
Like the previous poster said, she had a lot of back story on her characters and she probably thought everyone would realize that if they really thought about it.
She was wrong ... I didn’t even think about it.
But I don’t think she made an announcement per se.
I don’t see ANY gay overtones in the books.
Dumbledore is a typical ascetic scholar, IMO.
He wanted knowledge, not Grindelwald.