In Chapter 19, Angelou directly quotes the commentator of the famed boxing match between Joe Louis and Max Schmeling. Historically, this fight was important for two reasons: Louis was a black American, and Schmeling was a white German - in the late 1930s. People saw it as a victory of the USA over the Nazis, and for the African American population, viciously segregated and mistreated, it was a huge step in the (still continuing) dialogue on race in America.
If, in this scene, Angelou had simply described what happened in the fight and during the listeners' scene, the reader would understand the events. However, by using the direct quotations and integrating descriptions of the sights, smells, and appearances of the rapt audience, the reader becomes a part of the scene. The reader is not learning about what happened - the reader is experiencing the fight with Angelou and her community.