In chapters 8–10, why did the black students and white students who supported integration have to act as if the hatred did not affect them?

The black students, particularly Melba Pattillo Beals, the narrator of the memoir, tried to act as though they were not affected by abuse from white supremacists so that they could remain at the school and effectively integrate it. Melba learned from her protector, Danny, a soldier in the 101st Airborne Division, that she had to be a "warrior." She mimicked his confidence and steeliness in response to both physical and verbal abuse. Other members of the Little Rock Nine, perhaps unable to employ Melba's methods, became more solemn and withdrawn as a result of the abuse. Others found alternative ways of coping. For instance, Terrence Roberts, like the other boys, endured a lot of physical punishment, but, as Melba says, he "was always quick on his feet" and used that quickness to avoid further punishment.
In chapter 8, Melba mentions that she, Carlotta Ray, and Thelma Mothershed one day sat in the cafeteria with friendly white girls who told them that, though some of their friends would have liked to get to know the Little Rock Nine, they had been warned by the segregationists not to be kind to the black students due to the possibility of also becoming targets of violence and harassment.