It could also be related to a prophecy or an ancient pact. In the Naruto universe, there are often prophecies and old agreements that characters have to abide by. Minato might have learned of something that required him to seal himself, perhaps to prevent a greater catastrophe that was foretold in a prophecy.
One possible reason could be to protect the village. Minato is known for his self - sacrificing nature. By sealing himself, he might be containing a great evil or power that could otherwise destroy Konoha. For example, if there was a powerful enemy or a dangerous jutsu gone wrong, sealing himself could be a last - ditch effort to keep everyone safe.
Another reason could be related to his origin. In fanfic, if his Uzumaki heritage is explored in a way that makes him feel like a burden or an outcast more than in the original series. Maybe there are secrets about his family that make him question his own worth. For instance, if there are made - up prophecies or family curses in the fanfic that make him think he's doomed to bring misfortune, he could end up hating himself.
In some fanfics, Naruto might be made to hate Minato and Kushina due to a sense of abandonment. If the story is written in a way that emphasizes how Naruto grew up alone and suffering, he could project his anger onto his parents for not being there for him. For example, he might think that if they were alive, he wouldn't have had to endure the taunts and loneliness in the village.
There could also be a shift in the power balance within the ninja world. Other villages might see Konoha as weakened due to Minato's self - sealing and might take advantage of the situation, leading to more conflicts and power struggles among the villages.
In some versions of fanfiction, Naruto might use a new and powerful sealing jutsu that he has either created or learned specifically for this purpose. It could be a jutsu that combines his Uzumaki heritage's sealing knowledge with his own unique chakra control.
One reason could be that Minato values the original narrative and the way his story was intended to be told. Fanfiction can sometimes introduce elements that he might find inappropriate or not in line with the values and themes of the Naruto world. For example, some fanfictions might create overly dramatic or out - of - character scenarios for him, which he would not approve of.
It could be that in the fanfiction, there are made - up events that lead Naruto to hate Minato. For instance, if there is a plot where Minato was thought to have some dark secrets that affected Naruto's life badly, like being involved in some sort of conspiracy against Naruto without his knowledge. This would give a reason for Naruto to hate him.
Maybe it's because of the hardships Naruto endured due to Minato's actions. Minato's decision to seal the Nine - Tails in Naruto made him an outcast. In fanfiction, this could be exaggerated to the point where Naruto blames Minato for all his pain and suffering, leading to hatred.
One possible reason could be a miscommunication in the fanfiction. Maybe some secrets were kept from Naruto about his parents that made him feel betrayed when he found out, thus leading to hatred.
Often in fanfiction, the resemblance between Naruto and Minato can be for emotional impact. When other characters see Naruto looking like Minato, it can stir up memories and emotions related to Minato. This can create interesting character interactions, like when the older generation sees Naruto and is reminded of Minato. It also adds an extra layer to Naruto's character as he might start to understand more about his father through this physical resemblance, like how people might react to him differently because of it.
In some fanfictions, Naruto might distance himself because he discovers some dark secrets about the ninja world or his own past. These revelations could shock him so much that he needs time alone to process and figure out how to deal with them.