Maybe Naruto's parents believe he has some uncontrollable power within him. In the Naruto world, powerful and unpredictable abilities can be very dangerous. His parents might think that by banishing him, they can prevent him from accidentally harming the village or those around him. They may hope that in exile, he can learn to control this power on his own without endangering others.
One possible reason could be that Naruto discovers some dark family secret that his parents want to keep hidden. For example, if there was a connection between the Uzumaki clan and some forbidden jutsu, and they fear Naruto might be exploited because of it. So they banish him to protect the clan's reputation and his own safety.
It could also be due to a prophecy. If there was a prophecy that Naruto would bring great disaster to the village in the future, his parents, who are responsible for the village's well - being, might choose to banish him. They would be in a difficult position, having to choose between their love for their son and their duty to the village. However, this is a very hard decision and would likely be full of internal conflict for them.
Well, perhaps in the fanfiction world, Naruto's parents discover some kind of 'dark power' within him that they fear might be uncontrollable. They think that banishing him is the only way to keep the village safe from this potential threat. This could be a power that is different from the Nine - Tails' chakra and seems extremely dangerous to them.
One possible plotline could be that Naruto is banished due to false accusations of endangering the village, despite his parents being alive. His parents, Minato and Kushina, might be powerless to stop the decision because of some political intrigue within the village. Naruto then has to find his own way in the outside world, facing new enemies and making unexpected allies.
Maybe in the fanfiction, there were some political motives. Hiruzen might have been pressured by other hidden villages. They could have threatened Konoha if Naruto, as the Nine - Tails' jinchuriki, remained in the village. So, to avoid a potential war or conflict, Hiruzen made the difficult decision to banish Naruto. Also, it could be due to a misunderstanding. Naruto might have been in the wrong place at the wrong time during an incident, and Hiruzen misjudged the situation.
One possible reason could be for the protection of the village in a very extreme and controversial way. Minato might think that Naruto's presence is attracting too much danger and decides to banish him to keep the village safe.
It could also be due to false accusations. Perhaps an enemy ninja managed to frame them for a heinous crime. Like they were made to look as if they had conspired to assassinate an important figure from another village. This would lead to their banishment as their own villages would want to avoid a full - scale war because of their actions.
Well, in fanfiction, his family might banish Naruto due to differences in ideology. Naruto could be advocating for a more inclusive and progressive approach within the family, which goes against the traditional and conservative values of his family. They may see his ideas as a threat to the family's long - established order. Also, if there is a prophecy or some sort of family superstition related to Naruto that they misinterpret, they might banish him to avoid what they think could be a disaster for the family.
One possible reason could be that his parents are extremely busy with their own important ninja duties. In the Naruto universe, ninjas often have to go on dangerous missions. His parents might be so preoccupied with protecting the village from external threats that they simply don't have the time to notice Naruto. Another reason could be some sort of curse or spell that has made them oblivious to Naruto's existence. This could be part of an evil plot by an enemy who wants to isolate Naruto and make him feel alone.
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.
Maybe his parents are dealing with some internal conflicts or secrets. They could be involved in something dangerous or forbidden, and they think that by ignoring Naruto, they are keeping him safe from the consequences of their actions. It could also be that they are under some sort of spell or mind - control that makes them act as if they don't care about him.
In some fanfictions, it could be due to his parents being on a dangerous mission. They might have been forced to leave Naruto in order to protect him from the enemies who were after them. Maybe they thought that by abandoning him, the enemies wouldn't be able to find him as easily. Another reason could be that they were under some sort of dark magic or curse that made them act against their will. This could lead to them leaving Naruto without any choice.