One possible reason could be her involvement in the wizarding world. If her parents are muggles and they find out about the extreme dangers she faces in the magical realm, they might disown her out of fear for her safety. Another reason could be if she starts to show more loyalty to the wizarding community than to her muggle family, making them feel like she no longer belongs with them.
Well, perhaps in the fanfiction, Hermione discovers some dark family secrets. Her parents, being muggles, might not be able to handle the truth. For example, if she finds out she has some sort of magical heritage that is connected to dark magic in a way. Her parents, who are used to a normal, non - magical life, could be so horrified that they disown her. Also, if she starts using magic in ways that violate muggle laws in front of them, like accidentally or on purpose using spells to get things done quickly at home, they might react very negatively and disown her.
It could also be due to a prophecy. Suppose there's a prophecy that Naruto will bring great disaster in the future. His parents, believing in the prophecy, might decide to disown him in an attempt to avoid that future. They might think that by cutting ties with him, they can somehow change the course of events.
They could have been disowned if they took a stance on a political or magical issue that was against their parents' beliefs. For instance, if there was a conflict between pure - blood and half - blood wizards, and Harry and Ginny sided with the half - bloods when their pure - blood parents were firmly against it. This difference in ideology could cause a rift so large that their parents would disown them.
One possible reason could be a misunderstanding. Maybe he discovers some secrets about his parents that he misinterprets. For example, if he finds out they were involved in some dangerous or morally ambiguous activities in their youth that he doesn't fully understand at first.
Well, in some fanfictions, it could be that they're under the influence of some dark magic or a spell that makes them turn against Hermione. Or perhaps they're misinformed about her actions at Hogwarts and think she's a bad influence. Also, some writers might use it as a plot device to create a rift and then build a story around Hermione trying to fix things with her parents.
There could be some underlying mental health issues within the family. Perhaps her parents have some undiagnosed conditions that make them more prone to lashing out. In the fanfiction world, this could be explored further, like how Hermione tries to understand and deal with this aspect of her family situation while also dealing with the abuse.
A plotline could involve Naruto being disowned and then finding out that his parents were actually being controlled by an enemy. He then has to decide whether to forgive them or not while also dealing with the new threat. Or perhaps Naruto is disowned and he starts to form his own ninja group of outcasts, fighting against the traditional ninja villages that shunned him. This could lead to a whole new set of power dynamics and battles.
It could be related to some prophecy or superstition within the clan. They might think Naruto is a bad omen or something that goes against their traditional beliefs, so they decide to disown him.
She might throw herself into her studies even more. Since she has always been studious, she could use her academic pursuits as a way to distract herself from the pain of being disowned. She may also lean more on her friends in the wizarding world, like Harry and Ron, for emotional support.
Well, it could be that Harry ends up in a new magical community that accepts him for who he is, away from the shadow of his disowning parents. He might learn new types of magic that were not taught in his previous life with his family. He could also meet a mentor figure who helps him through the tough times. And then, he might use his new - found knowledge and skills to face his parents again, but this time with confidence and self - assurance.
One possible plotline could be Harry feeling extremely lost and alone at first. He might have to find a new place to live, perhaps with the help of his friends like Ron and Hermione. He could struggle with self - worth, constantly wondering what he did wrong to make his parents disown him.