In the original Naruto storyline, there is a focus on Naruto's growth, his friendships, and his journey to become a great ninja. Torture has no place in this positive growth - centered narrative. So this fanfiction completely goes against the spirit of the original by introducing such a cruel and uncharacteristic act.
The original Naruto series promotes values like loyalty, hard work, and respect among characters. Anko torturing Naruto in a fanfiction is a deviation as it violates the respect aspect. In the main story, Anko might be tough but not to the extent of torturing a fellow ninja, especially one as important as Naruto who is central to the story's positive message.
The original Naruto story has a clear arc of Naruto facing challenges through battles and training, but always with an underlying sense of hope and the presence of allies. The 'anko tortures naruto fanfiction' disrupts this by introducing a dark and negative scenario that is not in line with the typical upbeat and aspirational nature of the Naruto universe.