In fanfiction, Naruto might not care about Team 7 because of a past trauma that he associates with the team. It could be a failed mission where he blames the team for something going wrong. Or he might have had a vision of an alternate future where Team 7 causes great harm, and that makes him distance himself from them in the present.
One reason could be some sort of betrayal he feels. Maybe he discovers a secret that makes him think Team 7 was never truly his team. For example, if he found out that the village leaders had some ulterior motives for forming the team that involved using him.
Perhaps Naruto has some newfound power or a different ideology that makes him think he's above Team 7. He could have met someone who convinces him that his old team is holding him back from achieving greater things. It could also be due to a misunderstanding. Maybe he misinterprets an action of Sasuke or Sakura as them not really caring about him, and that causes him to lose interest in the team.
One possible reason could be that Naruto has faced so many betrayals and hardships in the fanfiction. For example, if his friends turned on him for some contrived reasons, it might lead him to stop caring. Another reason could be the constant failure in achieving his goals, like protecting the village but always being undermined by political intrigue within the fan - made story.
One possible reason could be that Naruto has finally realized that Sakura's heart has always been with Sasuke. After years of chasing after her and getting constantly rejected or overlooked, he just gets tired and decides to move on. He might start to focus more on his own personal growth and the other relationships in his life that are more reciprocal.
It could also be due to a sense of betrayal. If he found out some dark secrets about his family, like his father being involved in something bad that he couldn't forgive. This could make him turn his back on his family and not care about them at all.
She might be too busy with her own life in the Naruto universe. There are so many things like battles, relationships, and her own growth that she has to deal with. Fanfiction is just not on her radar.
It could be because of a power struggle. Suppose Naruto discovers a new, extremely powerful power within himself, but the village elders or some members of Team 7 are afraid of it. They try to suppress him. Feeling cornered and betrayed first, Naruto could then turn against them. He might believe that he has to protect this new power and use it for what he thinks is right, even if it means going against his old team.
One possible reason could be that Naruto has faced too many betrayals. Maybe his friends turned on him in the fanfic, which made him lose faith and stop caring.
One possible reason could be a sense of being undervalued. Maybe he felt that his teammates didn't fully appreciate his efforts during the Wave mission. For example, if Sasuke got most of the credit, Naruto might feel pushed aside.
Another reason might be related to a past event that Naruto unknowingly caused harm to one of the Team 7 members' families. Even if it was an accident, the emotional pain could make the affected member, and maybe the whole team, hold a grudge against Naruto. For instance, if Naruto's actions during a battle led to the destruction of a family's home, and a Team 7 member was from that family.
Perhaps in this fanfiction, Naruto has been influenced by some external force. It could be a dark entity that has corrupted his view of Team 7. He might see them as a hindrance to achieving some greater, more self - centered objective. Also, it could be that Naruto has had some sort of personal revelation about his past and blames Team 7, or certain members of it, for things that he now believes held him back in the past.
One possible reason could be a misunderstanding. Maybe his team made a decision without consulting him, which made him feel left out and thus led to hatred. For example, if they took on a mission without him, Naruto, who values being part of the team, might feel betrayed.