It could also be a part of a larger plan. Perhaps the Akatsuki sent him on a mission that was actually a trap set by Konoha. Konoha could have leaked false information to lure Deidara in and then capture him. Another possibility is that he got separated from his Akatsuki partners during a fight in Konoha and was then overpowered and captured.
Konoha could also try to rehabilitate Deidara in some fanfic ideas. They might see if they can turn him away from his violent and destructive ways. Maybe they'd assign some ninja with good persuasion skills to talk to him and make him see the error of his ways. They'd also keep him under strict surveillance during this process.
One possible reason could be that the fanfiction misrepresents the true essence of Konoha. Naruto has a deep connection to Konoha, and if the fanfiction distorts its values, he might despise it.
One possible reason could be to seek stronger opponents outside of Konoha. Naruto might feel that he has outgrown the training opportunities in the village and wants to face greater challenges.
Naruto might forgive Konoha because he realizes that holding a grudge won't solve anything. He has seen the destruction that hatred can cause, like during the Pain arc. So, he chooses to forgive in order to move forward and bring about positive change. Another reason could be his respect for the previous Hokages and their ideals for Konoha.
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.
Another reason might be that Naruto is seeking a greater purpose. In the fanfiction, his 'godlike' state could make him realize that there are threats out there that he can't face while being tied to Konoha. He may leave to protect the world on a larger scale, believing that he can be more effective away from the village.
One reason could be false accusations. Maybe some powerful individuals in Konoha frame Naruto for a serious crime he didn't commit. For example, they could plant evidence that he was involved in a plot against the village leaders. Another reason might be the fear of his power. If his strength grows too rapidly and uncontrollably in the fanfiction, the elders or some conservative forces in Konoha may decide to exile him to prevent any potential disasters. Also, political intrigue could play a part. If there are different factions vying for power in Konoha and Naruto becomes an obstacle or a scapegoat for one of them, they could manipulate the situation to get him exiled.
One possible reason could be false accusations against him. Maybe he's wrongly blamed for a crime he didn't commit, like being framed for a major attack in the village. This would lead the village leaders to force him out to maintain 'peace' and security.
There could also be political reasons. Some factions within Konoha might have seen Naruto as a tool or a threat to their own political power. His influence and popularity could have disrupted the existing power balance, leading to animosity from those who wanted to maintain the status quo.
One reason could be his power. His connection to the Nine - Tails makes him extremely powerful. In fanfiction, some in Konoha might fear this power and thus hate him. Another reason could be jealousy. Naruto becomes very popular and respected in the original story. But in fanfiction, some characters might be jealous of his achievements and turn that into hatred.