One possible reason could be political intrigue within Konoha. Maybe there are certain factions that see Naruto and Hinata as threats to their power. For example, they might be afraid of Naruto's influence due to his status as a hero and Hinata's connection to the Hyuga clan. Another reason could be a misunderstanding. Perhaps some false information is spread about them that makes Konoha turn against them.
It might also be related to some ancient prophecy or hidden clan secrets. Suppose there is a prophecy that says Naruto and Hinata's union will bring some kind of disaster to Konoha. Even if it's a false prophecy, the superstitious or power - hungry elements in the village might act on it and betray them. Also, if there are secrets within Hinata's Hyuga clan that are deemed dangerous by Konoha, they could be scapegoated for it.
One possible reason could be a misunderstanding. Maybe Naruto's newfound power is misconstrued as a threat. For example, if he discovers a new jutsu that the Konoha 11 don't understand, they might think he's going to use it against the village. Another reason could be the influence of an outside force. An enemy could manipulate the Konoha 11 into believing Naruto is a traitor, perhaps by forging evidence or using mind - control techniques.
One possible reason could be a misunderstanding. Maybe Hinata is misinformed about Naruto's actions or intentions. For example, she might be led to believe that Naruto has done something harmful to the village when in fact he's innocent.
One possible reason could be fear. Naruto is extremely powerful, and some in Konoha might fear that he could one day lose control of his power. Another reason could be political intrigue. There may be certain factions within Konoha that see Naruto as a threat to their power and influence. Also, jealousy might play a part. Naruto has achieved so much and has the love of many, and some might be jealous and thus plot against him.
One possible reason could be a sense of betrayal. Maybe Konoha made some decisions that directly or indirectly hurt Naruto and Hinata's families. For example, if the village had covered up some dark secrets related to the Hyuga clan or Naruto's parents, it could lead to their hatred. Another reason might be the way the village treats shinobi in general. If they feel that Konoha is too harsh or unfair in its treatment, like overworking or underappreciating them, it could be a cause for their dislike.
One reason could be to find a more peaceful place. Maybe after all the chaos in Konoha, they just want a quiet life away from it all. They might also leave to explore the world and discover new things together, like new jutsus or different cultures.
One possible reason could be a misunderstanding. Maybe some false information was spread in the village that made Konoha believe Naruto had done something wrong. In fanfiction, things can be exaggerated and misinformation can easily lead to a situation of betrayal.
One possible reason could be jealousy. Naruto is very powerful and some in Konoha might be envious. For example, some minor clans might feel that Naruto, as an outsider in a sense, gets too much attention and resources. Another reason could be fear. His Nine - Tails power is so immense that some might fear he could lose control and endanger the village, so they betray him to try and eliminate the 'threat' before it's too late.
In these fanfictions, it might be related to the secrets Naruto holds. For example, if he discovers something about Konoha's dark past that certain people don't want exposed. They would then try to get rid of him by making him look like a traitor. Also, there could be external forces influencing Konoha to turn against Naruto, like other villages spreading false rumors.
One possible plotline could be that Naruto discovers a deep conspiracy within Konoha that makes him feel betrayed. For example, he might find out that some of the village elders have been using him all along as a tool to gain power. So in his rage, he decides to take revenge on the village. He could start by using his shadow clones to create chaos and disrupt the normal operations of Konoha.
They might leave to seek new forms of power or knowledge. There could be things outside of Konoha that they believe will help them become better at their ninja skills. For instance, they might have heard of a special dojo or a hidden scroll in another land that could enhance their abilities.