Perhaps some authors are trying to explore the psychological aspects of both characters in extreme situations. By creating a scenario where Legolas is abused by Thranduil, they can dig deeper into how such a situation would affect Legolas' growth and development, as well as Thranduil's character flaws. However, this is a very unorthodox way of doing it and not in line with the general positive view of their relationship in the source material.
One reason could be a desire for a darker, more edgy take on the characters. Some fans like to explore the 'what if' scenarios that are completely different from the original narrative. They might want to add more conflict and drama to the relationship between Legolas and Thranduil.
I'm not aware of any specific 'legolas abused by thranduil' fanfiction that can be recommended. Fanfiction often varies greatly in quality and content, and this is also a rather dark and unorthodox concept. It's important to note that such themes might deviate from the original positive portrayal of the characters in the Tolkien lore.
It could also be a misinterpretation of the characters. Maybe the writer saw some of Thranduil's sternness or his actions in a wrong light and decided to take it to an extreme of abuse in their fanfiction. Another possibility is that they are trying to explore a very dark and angsty side of the relationship, perhaps to show how Legolas could grow and overcome such a difficult situation, but this is still a very unorthodox approach.
It could also be a form of catharsis for those who have experienced abuse in real life, though this is a rather controversial way of dealing with it. By writing or reading about abuse in a fictional context, they may feel they are processing their own feelings, but it can also be triggering for others. Another reason might be that some writers simply want to create shock value to get more attention for their work.
Some writers might be exploring dark themes for the sake of drama. They think it can create intense emotions and complex character arcs.
Some writers might be interested in exploring the darker side of human nature. They could use the well - known Batman - Robin relationship and twist it to show how power dynamics can go wrong. It's also possible that they want to create shock value to get more attention for their work.
One reason could be for shock value. Some authors like to create extreme and unexpected scenarios to get a reaction from readers. Another could be a different interpretation of Harry's character. Maybe they see some latent flaws in him that could lead to such behavior in certain extreme situations.
One reason could be that some fans want to explore the darker aspects of a character's life in a fictional and extreme way. They might think it adds depth or a different perspective to the character. But this is a rather controversial approach.
Some writers might be exploring dark or 'what - if' scenarios for shock value. They want to deviate from the normal, positive relationship portrayal to create something edgy.
Maybe some people want to create shock value. They believe that by writing about an abused Kuroko Tetsuya, they can attract more readers. However, this is unethical as it distorts the character's image. Also, it could be due to a lack of understanding of the positive themes in the original work, which leads them to create such inappropriate content.
One possible reason could be the exploration of dark and complex emotions. Some writers might want to dig deep into the characters' psyches by putting them in extreme situations like abuse. Another reason could be a way to add drama and tension to the story. By having such a difficult and controversial element, it can create a lot of emotional impact.