Anyone with half a brain could have potentially deduced that one.
Besides the fact in The Deathly Hallows, a younger Albus was known to spend time with another wizard in training, he was never ever associated with a woman (hell, even Snape that going on for him).
Though it never spelled it outright, he and Grindelwald were planning on taking over the world of magic together….as partners.
If the Ministry of Magic had a ‘sexual predator’ list, Dumbledore probably have been on the top of it. Let’s face it – the man sought out underage boys who had troubled histories and been abandoned by their families in one form or another. He took in both Tom Riddle and Harry Potter under similar circumstances. Not only that – he followed their whereabouts from a young age, until he approached them and cajoled them to come live in a far away land.
He gave them a ‘safe place’ and robes to wear and had them live up in a tower. Usually, those kinds of kids are put in basements or crawl spaces – so in theory they had it pretty good.
Naturally, the weirdo christian right, who think the books are evil because of magic, now have another reason to vilify the highly regarded series.