What personal values were inherent to Hassan?Why did these values compel him to accept responsibility for the items belonging to Amir, found in his hut? Why would he jeopordize his family.
In "The Kite Runner," Hassan was Amir's loyal friend and servant. They did everything together except go to school. Hassan was of a lower class and he was not permitted to attend school. Hassan was Amir's "kite runner."
Following Hassan's rape by the neighborhood bullies, and Amir's cowardly behavior, Amir was feeling very guilty. He expressed this guilt by trying to drive away the source of his guilt, which was Hassan. In a desperate effort, Amir hides his expensive watch among Hassan's belongings. Hassan is accused of stealing the watch, by Amir. Rather than tell on his friend, Amir, and defend himself, he lets Baba think he is a thief. Hassan's father takes Hassan and moves away. This type of loyalty and integrity is hard to explain. His love and loyalty to Amir overcame any thought of self. He simply could do nothing to bring harm or shame to Amir. He would rather accept the shame himself.
"Instead, when Amir betrays him a second time by telling Baba that Hassan has stolen from them, Hassan apologizes as if he committed the crime. Hassan and Ali leave Kabul and return to the Hazajarat region where the Hazara people have historically resided, but Hassan never holds a grudge against Amir for his actions."
You asked why? The idea is very difficult to put into words. Hassan was so pure in spirit, so honest, loyal and loving that he just couldn't understand that other's were not. He stood by Amir inspite of Amir's actions because that is the only thing Hassan knew to do. The idea of being bitter, holding a grudge, or getting even couldn't be in Hassans mind because it didn't dwell in his heart.