Perhaps a mind - control situation. Maybe an enemy was able to manipulate Naruto's mind, making him think that Konoha was an evil place that needed to be eradicated. It could be a powerful genjutsu or some other form of mind - influencing technique.
One possible motive could be a misunderstanding. Maybe Naruto discovers some false information that makes him believe Konoha has betrayed him. For example, if he's wrongly led to think that the village elders are planning to harm his friends or his sensei. Another motive could be the influence of a powerful and evil entity that has somehow managed to control Naruto's mind. It could use Naruto's strength to achieve its own goal of destroying Konoha.
One possible motive could be that they were somehow brainwashed. Maybe an enemy with powerful genjutsu got to them and made them believe that Konoha was a threat that needed to be eliminated.
Hinata would be heartbroken. She loves Naruto deeply and would likely try to understand his reasons. She would plead with him to change his mind, using her love for him as an argument, and maybe even offer to help him find a different solution to whatever problems he has with Konoha.
In fanfiction, Naruto might kill Konoha if he's under some sort of mind control. Maybe an enemy manages to manipulate his thoughts and turn him against the village. Also, if Naruto experiences a great loss because of Konoha's actions or inactions. Say, if his friends are killed due to Konoha's negligence in protecting them, and he blames the village as a whole. Or if he realizes that Konoha's system is so corrupt that it's causing more harm than good to the world.
One possible motive could be a deep misunderstanding. Maybe Naruto is framed for something he didn't do, and the Konoha ninjas turn against him. In his desperation to prove his innocence and defend himself, he might end up accidentally killing some of them.
Perhaps they are being manipulated by an outside force. An enemy of Konoha could deceive them into believing that the village is a threat to the greater good. This would lead them to take the drastic step of destruction. For example, if they are shown false evidence of Konoha planning to start a war that would cause mass destruction, they might act to stop it in what they think is the only way - by destroying Konoha.
One possible motive could be a sense of betrayal. Maybe Naruto felt constantly ostracized in Konoha despite his efforts to be accepted, and over time, that bitterness turned into pure hatred. For example, if he was always treated as an outcast by the villagers even after saving them multiple times, it could drive him to destroy the very place that never truly welcomed him.
It could be that Kiba has been involved in something that Naruto considers wrong. For example, if Kiba endangered the safety of the village or their friends, Naruto, being the protector - type, would take action against him. Or perhaps there was a misunderstanding between them. Kiba might have been framed for something, and Naruto, believing the false information, tries to 'destroy' Kiba in the heat of the moment.
One possible plot could be that Naruto is pushed to the brink by the village's constant mistreatment. The Kyuubi, sensing Naruto's anger and despair, influences him to turn against Konoha. They could start by attacking key strategic points in the village, like the Hokage's office and the ninja academy, causing chaos and destruction.
One possible reason could be that Naruto discovers some dark secrets about the village leadership that go against his values. For example, if he finds out that they have been using underhanded means to maintain power.