However, we can consider these factors from the book:
* Dudley's Transformation: In *The Order of the Phoenix*, Dudley starts showing signs of kindness and remorse, culminating in him defending Harry from the Dementors. This change, while initially confusing for Harry, likely sparked some hope for a better relationship. However, in *The Deathly Hallows*, Dudley is mostly absent. Harry only briefly sees him during the "Wedding of the Year" and notes his transformation has been "a bit too far" and that he now "looked like a large pink slug" with his newfound plumpness. This suggests a certain disappointment in Dudley's development and a lack of further connection between them.
* Harry's Focus: Harry's primary focus in *The Deathly Hallows* is on the Horcrux hunt and the escalating war against Voldemort. He's dealing with immense personal loss and the weight of carrying Voldemort's power, leaving little room for contemplation of Dudley.
* Harry's Acceptance: Harry has come to terms with Dudley's character and his own place in the Dursley family. He acknowledges that Dudley, despite his occasional kindness, is fundamentally different from him. This acceptance might not be considered "hate," but rather a recognition of the distance between them.
In conclusion, while there's no single event in *The Deathly Hallows* that makes Harry hate Dudley, we can see a combination of factors leading to a sense of distance and perhaps disappointment in Dudley's transformation. It's more accurate to say Harry simply has moved on, focusing on the more pressing matters of his life.