Maybe in the fanfiction, Naruto has discovered a new family or group of friends outside the village who are in need of his help more urgently. He has to prioritize them over the village that banished him. He could also be trying to teach the village a lesson about the consequences of their actions by refusing to help.
Perhaps Naruto has found a new purpose or community outside of Konoha that values him more. He may be so content with his new life that he simply doesn't want to get involved with Konoha's problems anymore. Konoha's actions towards him could have made him realize that his loyalty was misplaced all along.
Perhaps Naruto has been pushed too far by the villagers' continuous mistreatment. Even though he has saved them multiple times, they still show hostility or indifference towards him. So, in the fanfiction, he decides not to help Konoha anymore as a form of self - protection and to break free from this one - sided relationship.
The village would likely be in a state of panic. Since Naruto is very powerful, without his help, they might be vulnerable to attacks. They would have to find other ways to defend themselves, which could be difficult.
One possible reason could be that Naruto has seen the toll the position takes on those who hold it. Maybe he witnessed the stress and loneliness that previous Hokages like his father had to endure. He might want a more carefree life, exploring the world and spending time with his friends and family without the heavy burden of leading the village.
It could also be that the plot of the fanfiction has Naruto in a situation where talking might put him or his loved ones in danger. So, for their safety and his own, he chooses not to talk.
It could also be that Naruto has grown disillusioned with the politics in Konoha. Constant power struggles, nepotism, or unfair treatment of certain groups within the village might have pushed him away. He might feel that his help would only be enabling a corrupt system.
One possible reason could be Naruto's independent nature. He has always been someone who forges his own path. In the Naruto series, he doesn't rely on traditional forms of status or hierarchy. So in the fanfiction, he might refuse peerage because he wants to be recognized for his own efforts and not because of a title.
In fanfiction, it could be due to a prophecy. Suppose there was a prophecy that Naruto would bring great danger to the village in the future. Tsunade, despite her bond with Naruto, might believe in the prophecy and banish him to prevent the foreseen disaster. Also, it could be related to Naruto's power. If his power was growing too rapidly and becoming uncontrollable, Tsunade might banish him to protect the village from any potential harm his power could cause.
One possible reason could be political pressure. Maybe some powerful clans in the village see Naruto as a threat due to his growing power and influence. They might force Tsunade's hand to banish him to maintain their own status quo in the village.
One possible reason could be fear. The villagers have always feared the Nine - Tails within Naruto. His family might banish him out of this same fear, not wanting to be associated with the potential danger he represents. Maybe they think that by banishing him, they can keep the village safe from the Nine - Tails' power getting out of control.