To explore different aspects of their relationship. By having Ginny lie, it can show how much trust there really is between them. It can also be a way to show how they grow and learn from such situations. For example, if Ginny lies about something small at first and then it escalates, it can be a journey of self - discovery for both of them in the fanfiction.
For the sake of creating drama. Lies can easily stir up emotions and conflicts, which makes for an interesting plot. It keeps the readers on their toes, wondering when the truth will come out and how Harry will react.
Well, some authors might want to explore different character arcs. By having Ginny dump Harry, they can show Ginny as a strong - willed character who is not afraid to make tough decisions. It also adds drama to the story, as the relationship between Ginny and Harry is a central part of the Harry Potter universe.
Some 'Harry Hurts Ginny' fanfics exist because it adds a new layer of drama to their relationship. Their relationship in the original series was mostly positive, but exploring the negative aspects like Harry hurting Ginny can make for an interesting and complex story.
Some exist because fans like to explore different power dynamics in relationships. They want to see how Harry, as a central and powerful character, can influence Ginny's actions and decisions.
Perhaps in a fanfiction, Ginny lies to Harry about being in danger to draw him out for a surprise party that she has planned with all their friends. It starts with her sending him a false distress signal, and when he arrives, he is met with a celebration.
It might be for the sake of exploring unique and unexpected interactions between the two characters. Their relationship in the original books is complex, and this is a very different way to add a new dynamic.
Some people write it because they simply have different ideas about who Harry should be with. They might have a favorite character other than Ginny and want to explore a relationship between Harry and that character. Maybe they didn't like how Ginny was written in the original books and feel the need to rewrite the story in a way that suits their view.
Some exist because fans might feel that the concept of time travel in the Harry Potter series was not fully developed. They use bashing fanfiction to explore the flaws. For example, in the books, time travel seems a bit too convenient at times.
Some writers might do it for the sake of creating drama. By making Ginny a 'villain' of sorts, they can add more conflict to the relationship between Harry and Hermione.
Maybe the writers want to deviate from the typical 'happily - ever - after' story. They might feel that in the wizarding world, relationships are complex and not always smooth - sailing. So, the 'Ginny breaks Harry' plot allows them to explore more realistic relationship dynamics within the context of the Harry Potter universe.
It could be a way to explore Ginny's character more deeply. By having her stalk Harry, it shows her determination and the strength of her feelings for him. It also gives the writer a chance to show how she might deal with her emotions privately.