One possible reason could be that Naruto is afraid of endangering his friends. He has many powerful enemies, and he might think that by staying away from his friends, they won't be targeted. For example, Orochimaru was always after Sasuke, and Naruto might fear that his closeness to Sasuke could put Sasuke in more danger.
It creates a lot of tension. His friends will be confused and worried about him. This can lead to them trying to find out what's wrong with Naruto, which drives the plot forward as they search for answers.
One possible reason could be jealousy. Maybe Naruto has been getting more attention from the village elders or teachers because of his potential. His friends, feeling left out or overshadowed, might start to ignore him out of envy.
There could also be friends who are so loyal to Naruto that they would consider following his request if they truly believe it's for the greater good. However, they would be deeply pained by it. Kakashi, for instance, might understand Naruto's selfless nature but would also struggle with the moral and emotional implications of taking his life.
Typically, Naruto is known for his deep love and loyalty towards his friends. Fanfiction that has Naruto hating his friends is probably a deviation from the traditional understanding of the character. It might be used to explore some extreme scenarios, like if he was under some sort of mind control or if there was a huge misunderstanding. But in the mainstream Naruto - themed fanfiction, this is not a common occurrence.
In this fanfiction scenario, Naruto and his friends would likely be extremely confused by Cell. Naruto might immediately jump into action, ready to fight. His friends, like Sasuke, would probably assess the situation carefully. Maybe Sakura would be a bit scared at first but then gather her courage. They would have to quickly figure out Cell's abilities, which are very different from the foes they usually face in their own ninja world.
Naruto's power might also be affected. If he was betrayed, he could lose the will to fight or train. He might even start to doubt his own purpose. This could lead to a decline in his abilities, which in turn could put the village at risk if he was its main protector.
In some fanfics, Naruto might be depicted as hating his friends due to a misunderstanding. For example, if a false rumor spreads about his friends betraying him, he could start to harbor negative feelings. Another reason could be a dark magic or curse that alters his perception of his friends, making him think they are not who they seem.
In some fanfictions, Naruto protects his friends by using his new and improved jutsu. For example, he might develop a more powerful Rasengan to fend off stronger enemies. He also uses his quick thinking and ability to sense danger, which he has honed over time. His unwavering loyalty drives him to put himself in harm's way without hesitation, always being the first to jump into a fight when his friends are threatened.
In fanfiction, Naruto jumping in front of his friends could be a heroic act. Maybe he's protecting them from an incoming attack. It shows his selfless nature, always ready to sacrifice for those he cares about.