In the brown paper bag that the children see Mr. Dolphus Raymond continually carry, there is only Coca-Cola. Mr. Raymond, who is from a reputable family, tells the children that believing him an alcoholic provides the townspeople a reason that they can reconcile with his desire to live with a black woman on the other side of town. The alternative--that he prefers blacks to whites--is too counterculture for them to reconcile with a name such as Raymond's.
And, so, the children discover that Mr. Raymond is not, in fact, "an evil man" when he has emotionally upset Dill take a sip from his bottle concealed by the paper bag.
"Dill, you watch out,now," I warned.
Dill released the straws and grinned, "Scout, it's nothing but Coca-Cola."
Mr. Raymond sat up..."You little folks won't tell on me now, will you? It'd ruin my reputation if you did....
you see, they could never, never understand that I live like I do because that's the way I want to live."
Indeed, Mr. Raymond is a "mockingbird," just as Boo Radley and Tom Robinson are. For, he is not allowed the freedom to be truly himself; instead, he is misjudged by others who must categorize people in their society, judging him by their societal mores.