In Chapter Two, Khaled Hosseini clearly delineates the oppression of the Hazara community with sensitivity; the social stigma that attaches to Hassan and Amir's accidental discovery of the Hazara people's history tells us volumes about Hazara suffering.
In the chapter, Amir relates how Hassan has always been made fun of by people in their little community. Hassan's shame is compounded for two reasons: his mother was known for her infidelity to his father, and his own Hazara features plainly announce his lowly heritage. Other children in the neighborhood frequently address Hassan as a flat-nosed 'Babalu' or Boogeyman. In one of his mother's old history books, Amir learns that the Hazaras are also known as 'mice-eating, flat-nosed, load-carrying donkeys.'
The truth is that, Amir's people, the Pashtuns, have always oppressed the Hazaras. Because Hazaras are Shia Muslims and Pashtuns are Sunni Muslims, the enmity between the two communities continues to this day. When the Hazaras tried to defeat the Pashtuns in the 19th century, the Pashtuns had reacted mercilessly. The will of the Hazara people was crushed through pogroms (organized slaughter/massacre), the destruction of Hazara land and property and the sale of Hazara women into servitude. To make matters worse for Hassan, his mother, Sanaubar, had joined with the larger Pashtun community in ridiculing both Hassan and his father, Ali.