Maybe they had a bad experience related to the ideas in romance novels, like a broken heart and they associate the genre with false hopes.
Some people might be very conservative and think that the content in romance novels is too 'racy' or goes against their moral values. However, this is a rather narrow - minded view as most romance novels are just about love and relationships. Another reason could be that they are trying to make a statement against the so - called 'frivolous' nature of the genre, but that's also unfair as there are many well - written and thought - provoking romance novels.
Maybe they had a bad experience related to romance that made them resent anything romantic, including the novel.
Maybe they have a very extreme view. They might think light novels are full of unrealistic content that misleads readers, especially young ones. So they want to get rid of them all by burning.
It could be a misinterpretation of the character. Maybe the writer has a very different view of Naruto's personality. They might think that some of his self - sacrificing actions in the original series are signs of masochism, which is a wrong understanding. Also, some writers might just be exploring extreme and different ideas without considering the impact on the overall Naruto fan community. Since the Naruto world has a lot of room for interpretation, they might take it to an extreme and inappropriate direction.
One possible reason is a misunderstanding. The hero might think that they are in love with the person they marry, but later find out it was all a mistake. For instance, they might have misinterpreted their feelings of friendship or gratitude as love. Also, external threats could be a factor. If there is a threat to the hero's family or community, they might marry someone else as a way to protect them.
Some writers might be influenced by other works in the BDSM or 'lemon' genre and try to incorporate it into the Naruto universe just for the sake of creativity in a very different and often inappropriate way. But this completely distorts the positive and heroic image of Naruto and Anko as they are in the original series. It could also be a way for a very small group of people with specific and not - so - mainstream interests to express themselves, but it's not a healthy or appropriate way within the context of the Naruto fandom.
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 be due to some abnormal psychological factors. However, this is not a healthy or normal interest as it involves inappropriate and disrespectful content towards others.
Some people might write it for shock value. They want to create something that is so out - of - the - box and unexpected that it grabs people's attention. It could also be a way for them to explore very extreme and dark 'what - if' scenarios in the Harry Potter universe, even if it goes against the original story's essence.
One reason could be to explore a completely different side of the characters. Maybe the writer wants to see how the Dragon Ball universe would react to such a scandal. Another reason might be for shock value, to get readers' attention with a very unexpected plot twist.
Perhaps for shock value. Some writers might think that creating a very controversial and unexpected plot would draw attention.