Some people might write them out of jealousy. For example, if they prefer other characters and feel that Naruto, Hinata, or Sakura get too much attention in the original series, they might write bashing fanfics. It's a rather immature way to deal with their feelings though.
There could be a sense of wanting to create shock value. By bashing popular characters like Naruto, Hinata, and Sakura, they might think they can attract more readers who are curious about this unorthodox take. However, this often backfires as many fans of the original series dislike seeing their favorite characters being bashed.
It could also be that they have a different vision for Naruto's character arc. They might think that Hinata and Sakura held Naruto back in some ways in the original story, so they create fanfiction to show what they believe Naruto could have achieved without their influence. Additionally, some might just be expressing their dislike for Hinata and Sakura's personalities as they were portrayed in the official story.
Some people write it because they don't like Sakura's character. Maybe they think she's too whiny or not as strong as she should be in the Naruto series.
Some people write it because they might not like the characters of Ino and Sakura. Maybe they think their personalities are annoying or they don't like how they interact with Naruto. So, they create fanfictions to express their negative feelings towards them.
There are a few reasons. For one, some writers might have a different vision for Naruto's character development. They think that the original series didn't do enough to showcase Naruto's full potential. And they see Ino and Sakura as obstacles to that. Also, it could be a way to gain attention. If they create a controversial fanfiction where they bash Ino and Sakura to boost Naruto, it might attract more readers who are either interested in this new take on Naruto or are also not fans of Ino and Sakura. Additionally, it might be a form of creative expression for those who have strong feelings about the Naruto characters and want to reshape the story in a way that satisfies their own ideas about who should be the central and most important character.
Some people write 'naruhina sasuke and sakura bashing fanfic' because they are die - hard fans of the Naruhina pairing. They might feel that Sasuke and Sakura somehow get in the way of the Naruhina relationship in the original story, so they create fanfics to emphasize Naruhina more by bashing the other two characters.
Some people write it because they want to explore alternative scenarios. Maybe they didn't like the way Team 7 was portrayed in the original and want to show their own view.
Some people write it because they may not like the canon relationship between Sasuke and Sakura. Maybe they preferred Sasuke with another character or just didn't like how their relationship developed in the original story. They use fanfiction as a way to explore their own ideas of what could have been different.
In my opinion, it's not very ethical. Naruto, Hinata, and Sakura are well - loved characters. Writing bashing fanfiction can be disrespectful to the original creators and the fans who adore these characters. It can also create a negative atmosphere within the fan community.
Some people write it because they want to explore alternative storylines. Maybe they think the original Team 7 is too 'perfect' in a sense and they want to see how things would play out if they were different. Or they might just not like certain aspects of Team 7 and use the fanfic as a way to express their dissatisfaction.
I don't really encourage 'bashing' fanfics as they are often mean - spirited. However, if you're just curious, you might search on some niche fanfic websites. But remember, Naruto and Hinata, and Sakura are all well - developed characters in the original series, and bashing them in fanfics goes against the spirit of the source material in a way.