I'm not sure. Fanfiction can be very subjective. Some might find it interesting as it offers a different take on the characters' relationship, but it also goes against the more common portrayal of their bond in the original series.
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.
A scenario could be that Sasuke blames Sakura for something that went wrong in his revenge plan. Maybe she unknowingly did something that set him back, and in his anger and single - minded focus on revenge, he starts to hate her. Another possibility is that in the fanfic world, there is a misunderstanding. Sakura is misinterpreted as being involved with someone who has wronged Sasuke, and this causes him to hate her without really knowing the truth.
In lemon fanfiction, the 'sakura hates sasuke' scenario can stem from various factors. One possibility is that Sasuke's past actions, such as his association with dark forces or his disregard for the safety of the village which Sakura holds dear, could make her resent him. Additionally, if in the fanfiction's world, Sasuke has made decisions that directly oppose Sakura's efforts to build a relationship or a peaceful environment, it would be understandable for her to hate him. For instance, if he undermines her medical work in the village or her attempts to bring the shinobi world together.
Well, one possible reason could be that Sasuke's mistake might have put their team in great danger. For example, if his actions led to the enemy getting an upper hand during a battle, endangering not only his life but also those of his comrades like Sakura. Sakura, who values the safety of the team, would then resent Sasuke for his mistake.
One common scenario is when Sasuke betrays the village. Sakura, who is loyal to the village, may then feel hatred towards him. She has grown up in the village and values its safety and well - being, so Sasuke's betrayal would be a major blow to her and could turn her love into hate.
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.
The relationship would become very tense. Naruto would likely avoid Sakura and Sasuke. There would be no more of the friendly banter or the complex emotional triangle that was there before. It's a complete shift from their normal relationships in the original story.