I think the best way to react is to recognize it as a very inappropriate deviation from the original 'Harry Potter' narrative. The relationship between Dumbledore and Harry in the books is based on respect and mentorship. This kind of fanfiction not only distorts that relationship but also spreads a negative and disturbing message. It's better to focus on fanfictions that stay true to the spirit of the original work and promote positive values rather than engaging with or promoting this type of inappropriate content.
In proper 'Harry Potter' lore, Dumbledore is a mentor figure, not involved in any such inappropriate relationships. In fanfiction, this is a very non - canonical and disturbing concept. There is no evidence from the original books to support such a plot in fanfiction. It's often a case of some fanfic writers taking creative liberties too far and creating inappropriate and untrue scenarios.
It is not okay. Fanfiction often expands on the existing world and characters, but when it involves abuse like this, it can have a negative impact on how readers perceive the characters. Snape had his difficult relationship with Harry in the original series, but 'abuse' is a very extreme and inappropriate way to represent that relationship in fanfiction.
Dumbledore, as Harry's guardian in the fanfiction, would probably use his influence in the wizarding world. He could make sure that Harry is taught by the best teachers at Hogwarts. He'd also be there to offer advice and guidance, especially when Harry faces challenges like dealing with Voldemort or other dark forces. For example, he might teach Harry some advanced defensive magic privately to better protect himself.
Well, in some fanfictions, Harry might attack Dumbledore if he discovers that Dumbledore has been using him as a pawn in a bigger game all along. This feeling of betrayal could drive him to lash out. Also, if there is a prophecy that he misinterprets to mean Dumbledore is a threat to his future or the future of his friends, that could be a motive.
Snape can be a prominent character. Given his complex relationship with Dumbledore and Harry, his perspective could add a lot to the story. He might have some insights into Dumbledore's actions that Harry doesn't know about, and his reactions to Harry's blaming could vary from being scornful to having a moment of understanding. Luna Lovegood could also be a part of it. Her unique view of the world might make her offer some different viewpoints on the situation between Harry and Dumbledore.
Dumbledore might give Harry advanced spellcasting training. He could teach Harry some of the more complex and ancient spells that are not commonly taught at Hogwarts.
Hermione could be a main character. She might use her vast knowledge to help Harry and Dumbledore in their adventures. For example, she could research ancient spells or potions that are crucial for their mission.
Perhaps there are safety concerns for the students that Dumbledore is not addressing adequately. Harry, having a strong sense of responsibility for his fellow students, may feel that the only way to ensure their safety is to remove Dumbledore from his position. He might believe that Dumbledore's actions or inactions are putting the students at risk, and thus he takes matters into his own hands.
The relationship would become very strained. Harry's rejection would likely make Dumbledore re - evaluate his actions and how he has interacted with Harry. Dumbledore might be shocked at first, since he probably thought Harry was on the same page as him most of the time.