In such a fanfic, one possible reason could be Naruto's feeling of being left out. Maybe he sees Sakura's constant focus on Sasuke and feels neglected in their friendship triangle. Another reason might be jealousy. If Naruto has unrequited feelings for Sakura, seeing her love for Sasuke could turn to hatred over time.
Well, perhaps in this 'naruto hates sakura and sasuke fanfic', Naruto hates them because of a series of misunderstandings. For example, Sasuke may have made some decisions that Naruto thought were against their village or friendship, and Sakura might have blindly sided with Sasuke in Naruto's eyes. This could lead to Naruto's hatred towards them.
One possible reason could be jealousy. Maybe in the fanfiction, Naruto feels overshadowed by Sasuke in Sakura's eyes, which leads to his hatred. Another reason might be that he perceives their relationship as a threat to his own bonds with them. For example, he could think that Sasuke and Sakura's closeness excludes him in some way.
Maybe in the fanfic, Sasuke has done something to betray Sakura's trust. For example, he might have left the village again without considering her feelings.
One reason could be that in some fanfiction, the characterizations of Sasuke and Sakura might be off. Maybe Sasuke is portrayed as overly cruel to Sakura in a way that doesn't seem true to his character in the original series. Another reason could be that the storylines in these fanfictions are too clichéd, like always having Sasuke constantly reject Sakura in the same uninteresting ways.
One possible reason could be a misunderstanding. Maybe Naruto misinterprets some of Sasuke and Sakura's actions as being against him or the village. For example, Sasuke's quest for power might seem like a threat to Naruto, and he could misread Sakura's loyalty to Sasuke as a form of betrayal to their friendship.
One possible reason could be jealousy. Maybe fem Sasuke is jealous of Naruto's natural charisma or his ability to make friends easily. Another reason might be related to their different goals. If fem Sasuke has a very different view of how to save or change the ninja world compared to Naruto, it could lead to hatred.
Some fanfic authors might write it as a form of wish - fulfillment. They might prefer the Naruto - Sakura relationship more than the Sasuke - Sakura one. So, they create a scenario where Sakura turns to Naruto in a romantic way. Additionally, it could be a way to explore the characters' personalities further. For example, how Sasuke would handle being betrayed and how Naruto would deal with being involved in such a situation. It gives a chance to dig deeper into their emotional and moral aspects.
Well, Naruto could hate Sakura and Sasuke because in the NaruHina fanfiction context, Sakura might represent the past and all the times Naruto felt rejected by her. She always had eyes for Sasuke. And Sasuke, his actions were often self - centered and caused Naruto a great deal of distress. Naruto, as he falls for Hinata, starts to realize that Hinata is always there for him. Unlike Sakura, who is always pining for Sasuke. So, Naruto's feelings towards Sakura and Sasuke change to dislike as his relationship with Hinata blossoms.
One reason could be jealousy. If in the fanfic there's another character who Sasuke is close to, Sakura might be rude out of envy. Another reason could be that she feels betrayed by Sasuke in some way, like if he made a decision without considering her feelings. Also, it could be part of her own character development, starting off rude to show her flaws and then changing later.
Another reason might be related to their different ideologies within the ANBU. Naruto may have believed in a more collaborative and friendly approach within the organization, while Sasuke might have been more focused on individual achievement and power. This fundamental difference could lead to Naruto hating Sasuke in the fanfiction.
It could be because of a dark power corrupting Sasuke. Maybe an ancient evil force takes over him and makes him see Sakura as an enemy. In some fanfics, this kind of external influence can completely change a character's actions. Also, it might be related to Sasuke's pursuit of power. If he believes Sakura is standing in the way of his ultimate power - seeking goal, he could be driven to kill her.