One consequence could be that the fanfirls in the fanfic might get sad or angry at being hated. They might stop supporting Naruto in the fan - created stories.
In the fanfic itself, it could change the story's direction. Maybe the fanfirls try to get revenge on Naruto for hating them, which could create new plotlines and challenges for Naruto to face. Or perhaps Naruto tries to find a way to make peace with them, which would also be an interesting development in the fan - created story.
One consequence could be that it makes his character seem more aloof in the fanfic world. People might see him as unfriendly or unapproachable, which could change the way other characters interact with him.
He might become withdrawn.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.
One consequence could be that Naruto leaves the village. He might go on a journey alone, seeking a new purpose away from the place that has caused him so much pain. This would be a major change from his original story where he was so attached to the village.
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 consequence could be that fans who really respect Kushina's character might be more hesitant to engage with fanfictions. If they know that Kushina, in a sense, wouldn't approve, they might feel guilty or less interested in exploring those fictional works.
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.
Maybe he just doesn't like the way some fanfirls act in the fanfic. They might be too obsessive or change his character in ways he wouldn't like.
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.
One consequence could be that he leaves the village. He might go off on his own to find a new place where he feels accepted and can start anew.
It could also lead to some division among the Naruto fandom. Those who support Sakura's view might be more critical of fanfiction, while those who love fanfiction might not like Sakura as much because of her stance. For example, in online Naruto communities, there could be debates and arguments about whether Sakura is right to hate fanfiction.