Well, it could be that the fanfiction distorts the original Naruto story in ways that are unappealing. Maybe it goes against the core values or the character development in the Naruto universe.
It might also be that the quality of the 'fallen anegl' fanfiction is simply bad. Bad writing, inconsistent plotlines, or just a general misrepresentation of the Naruto world could lead to the idea that Naruto would hate it. Fanfictions are often a way for fans to explore different scenarios, but if it's not done well, it can feel like a desecration of the beloved Naruto series.
Some fans who like that particular fanfiction might feel targeted or offended. It could create a bit of a divide in the community.
One possible reason could be that the fanfiction misrepresents the Uzumaki clan or Naruto's connection to it. Naruto has a deep and complex relationship with his Uzumaki heritage, and if the fanfiction distorts it, he might dislike it.
It could also be due to the overall tone and plot of the fanfiction. If the fanfiction has a dark or negative theme and Yasaka is a part of that in a way that makes Naruto seem to 'hate' her, it might be because the writer wants to create some sort of conflict. However, this may not align with the original essence of Naruto's character, who usually tries to understand and befriend rather than hate without a good reason.
Maybe Naruto, as a character with his own set of values and storylines in the original Naruto universe, clashes with the concepts often presented in Olympus - related fanfiction. For example, the Naruto world has its own unique power systems, cultures and ethics which might be very different from what is typically found in stories related to Olympus.
Maybe Naruto has some personality clashes with the Hyuuga characters in the fanfic. For example, the Hyuuga clan is known for their traditional and sometimes rigid ways, which might go against Naruto's more free - spirited nature.
Maybe it's because of the different power systems. Naruto has chakra and his ninja abilities, and Rias has her devil powers. If in the fanfiction these power systems are not properly integrated or if one overshadows the other in an unappealing way, Naruto could be depicted as hating Rias. Say, if Rias' devil powers are made to seem too overpowering and it goes against Naruto's sense of fairness in combat, it could lead to such a scenario.
It could be that the fanfiction simply doesn't meet Boruto's standards for what the Naruto universe should be like. He has grown up in that world and has his own ideas about how things should be. Fanfiction can be very hit - or - miss in terms of quality and faithfulness to the source material. If it's of poor quality or changes things too much, Boruto might hate it.
One reason could be a misinterpretation of their complex relationship. In the original story, Naruto actually cares deeply for Sasuke. But in fanfiction, the author might be exploring a 'what if' scenario where Naruto's frustration turns to hate due to Sasuke's repeated betrayals. Another reason could be to create a more angsty or dramatic plot. By having Naruto hate Sasuke, it can introduce new conflicts and character developments that are different from the canon.
It could be that the fanfiction creates a forced or contrived situation. Naruto is a character known for his determination and positive energy. A plot where he hates his sister might not fit well with the overall Naruto universe. It might be a way for the author to create drama in a rather unappealing way that doesn't resonate with the essence of the Naruto character.
Maybe the fanfiction portrays Hinata in a way that doesn't align with her true character. For example, it might make her overly aggressive or weak in a way that doesn't fit the original concept.