The issues of racism and segregation comprise the central motif of the novel, & are the aspects by which all characters are defined. The society is split between people who fear and hate (such as the members of the jury who convict an innocent man of rape because of his race), and those like Atticus and Calpurnia, who show understanding and sympathy towards those who might be different or less fortunate. These values are carried onto Jem and the protagonist Scout. For example, when Scout brings Walter Cunningham home for dinner and then mocks his table manners, Calpurnia scolds her and says that all guests should be treated with respect no matter what their social station. Atticus also forms judgments based on behavior and not their background. Unlike Aunt Alexandra, who calls poor people like the Cunninghams "trash" because of their socio-economic status, Atticus tells his children that any white man who takes advantage of a black man's ignorance is "trash."
Throughout the story blacks are referred to as ‘niggers’, and those who support them or show them any kindness, ‘nigger lovers’. Scout fights many children in the schoolyard (and her cousin) due to their misunderstanding of Atticus' courage. Hypocrisy also runs deep in the so-called good people of the town: the churchwomen form a missionary circle to support the work being done with the "heathen savages" in Africa, but condemn those who fight for the rights of the black residents in their own town.
The prejudice of Maycomb is not based solely on race, however. Anyone who is different, or who remains outside the social circles, is ostracized and segregated. Boo Radley is labeled as a monster and outcast because he never leaves his home. It is not enough to just leave him alone – he is an object of gossip and games. The children re-enact stories they have heard about him and dare each other to spy on him. Atticus dissuades his own children from doing this, and at the end of the book, Scout and Jem understand Boo's role as a mockingbird, bringing good to the community in return for nothing.
The Ewell family should not be overlooked as being the victims of prejudice. The Ewells, although white, are almost as despised as the Negroes. They live in poverty, removed from respectable society in their own segregation. They are targets of scorn and derision. Mayella, a girl ruled by an alcoholic and violent father, is offered help by a man who should be her inferior. Tom Robinson is possibly the only man who has ever shown her any respect and, misreading this, she makes inappropriate overtures. When this is discovered her father forces her to turn the situation to their advantage by accusing Tom of rape. This incident shows that racism creates a cycle that continues far beyond any initial incident.
The issues of racism and segregation affected the character and protagonist in a profound way that caused him to be concerned about the life of a negro man who was accused of raping a white female. Atticus Finch, the character and protagonist, was against racism and realized that the negro man would not get a fair trial if he did not defend the negro man.