Maybe Harry has seen a different side of Draco that others haven't. He could have realized that Draco was just a product of his upbringing and the difficult situation he was in.
It's possible that Harry defends Draco out of a sense of fairness and seeing the good in Draco that others don't. He could reveal some secrets about the situation that Draco was in that would change everyone's perspective. For example, if Draco was being blackmailed by a more powerful dark wizard to do certain deeds, and Harry found out about it. Then he would present this information at the trial, which would lead to Draco being acquitted or at least having a much lighter sentence.
It's popular because it offers a fresh take on the relationship between two characters who are often at odds in the original 'Harry Potter' series. It creates a sense of redemption for Draco, who was a bit of a bully in the books, and shows that he can be a better person by defending Hermione.
In some fanfictions, it could be because Draco shows a different side of himself. Maybe he protects Harry from other threats secretly. For example, he might use his knowledge of the Slytherin world to keep Harry out of danger.
One reason could be the complex relationship they have in the original series. Fanfic authors often expand on that. Maybe Draco realizes Harry's importance in the fight against the real evil, like Voldemort, and so he becomes protective. It also adds an interesting dynamic to the story, making it more appealing to readers who love exploring different character relationships.
Maybe it's because Draco has a complex relationship with Harry in the original story. The fanfiction allows him to explore different aspects of their relationship, like a deeper understanding or a different kind of friendship that wasn't fully shown in the canon. It gives him a chance to see their story from new perspectives.
In fanfictions, Draco may yell at Harry due to jealousy. Harry is often the center of attention and gets all the glory. Draco, who comes from a proud pure - blood family, might feel overshadowed and this could lead to him yelling in frustration.
In some fanfictions, Harry might defend Snape because he comes to understand Snape's complex past. Snape was in love with Harry's mother, Lily, and his actions, though often harsh towards Harry, were sometimes motivated by his love for her and his role as a double agent against Voldemort. Harry, being a character who grows in understanding, could defend Snape once he learns these truths.
Well, it depends on the specific fanfiction. Some fanfic writers like to play with power relationships and might write a scenario where Draco appears to 'own' Harry in a symbolic way. However, this is not based on the canon of the Harry Potter books at all. It's just the creativity of the fanfic authors running wild. There are also many other fanfictions where such a concept doesn't exist at all.
In some fanfictions, Draco might brush Harry's hair as a sign of a newfound closeness or a different kind of relationship developing between them. It could be a moment of tenderness in a story where their traditional rivalry has transformed into something more affectionate.
At first, they might be shocked and a bit confused about being twins. But as time goes on, they start to trust each other more. They could share their secrets and fears, like Harry might tell Draco about his nightmares of Voldemort, and Draco might open up about the pressure from his family.