Maybe she's tired of it because she has her own story and character development in the original series, and fanfictions often deviate from that. She might feel that these fanfictions don't do justice to her true self.
Well, Kakashi is a very cool and mysterious character. He has a lot of skills and knowledge that Sakura can learn from. And Sakura, she's grown so much as a character. People like to explore how their different personalities can interact. Kakashi's calmness and Sakura's determination make for an interesting combination in fanfiction.
Maybe it's because in the original series, Kakashi seemed to focus more on Naruto and Sasuke due to their special circumstances. So in fanfictions, this can be exaggerated to show Sakura being neglected as she was often seen as the 'normal' one among them.
Another possibility is that Sakura would feel really down at first. But then, inspired by her love for Sasuke or her desire to protect her friends, she would pull herself together. She could approach other more approachable senior ninjas for advice on how to train without Kakashi's guidance. For example, she might go to Shizune, who could give her some basic medical - ninjutsu training tips that she could build on herself. And she could also practice her physical strength training on her own, like doing extra push - ups and running drills in the forest.
The appeal lies in the dynamic between Kakashi and Sakura. Kakashi is a highly skilled and respected ninja, and seeing him come to Sakura's rescue plays into the idea of the strong protecting the vulnerable. It also shows their relationship, which can be explored in different ways in fanfiction.
People like it because it offers a different take on the Naruto universe. Kakashi and Sakura have a unique dynamic in the original series, and fanfiction allows for exploring a romantic relationship that wasn't fully developed in the anime or manga.
Someone might write it to explore different character dynamics. Kakashi and Sakura have a certain relationship in the original Naruto series, and this gives the writer a chance to twist it. Maybe they want to create a more suspenseful or romantic story.
Well, they are an interesting pairing because of their age difference and different experiences. Kakashi is much older and has a lot of battle experience and a tragic past. Sakura, on the other hand, is a young and ambitious kunoichi. The contrast between their maturity levels and life stories can create a lot of interesting dynamics in fanfiction. For example, Kakashi can be a mentor figure to Sakura in some stories, which then can develop into something more romantic as Sakura grows and matures.
Some people write 'kakashi sakura hate fanfic' because they simply don't like the character dynamic between them in the original work. Maybe they think Sakura is too whiny or that Kakashi is too aloof towards her, and they want to explore a more negative version of their relationship.