Naruto's hatred for the world in fanfiction might also lead to a change in his powers. His negative emotions could either make him lose control of his existing powers or lead to the development of new, more dangerous powers that are fueled by his hatred. This would pose a great threat not only to his enemies but also to those he once considered friends.
He might become withdrawn. Instead of being the energetic and outgoing Naruto we know, he could isolate himself from his friends and the village. This would change the whole dynamic of the relationships in the fanfic.
He may dislike it because he feels that it undermines the real struggles and achievements of the ninja. In fanfiction, things might be made too easy or unrealistic. He has fought tooth and nail for everything in his ninja life, and seeing it made into something that doesn't represent that in fanfiction would make him hate it.
His relationship with Jiraiya could be affected. Jiraiya has a strong connection with the toads, and if Naruto hates toads, it could create a rift between him and his mentor. This could lead to Naruto losing an important source of guidance and support in the fanfiction.
The consequence could be that the fanfiction community might feel less connected to Minato as a character. Since he is a significant part of the Naruto universe, his dislike of fanfiction could make some fans less enthusiastic about including him in their fan - created stories. This might lead to a shift in the focus of fanfiction towards other characters who are more 'welcoming' of fan interpretations.
One reason could be jealousy. If in the fanfic, Sakura gets closer to someone else Naruto cares about, like Sasuke in a different way than he expected, it might make him hate her. For example, if Sakura teams up with Sasuke against Naruto's wishes in the fan - created plot.
In some fanfics, there could be a misunderstanding. Suppose Kushina did something that Naruto misinterpreted as harmful to him or his friends. This misinterpretation could lead to his hatred. For example, if Kushina was involved in a mission that Naruto thought put the village at risk, but in reality, she had no choice.
In this type of fanfic, Naruto might have had his own dreams and goals for the village that Sasuke and Sakura are unknowingly thwarting. Sasuke may be on a path that Naruto sees as leading to destruction, and Sakura, by being on Sasuke's side, is also seen as an obstacle. Naruto's hatred then stems from his strong sense of justice and his love for the village.
One possible reason could be jealousy. Maybe in the fanfiction, Jiraiya gives more attention to another character, and Naruto, being young and impulsive, starts to hate him for it.