Dolphus Raymond, like the mockingbird, does no harm to anyone. In fact, in his encounter with the children during Tom Robinson's trial, his words and actions imply that he is a gentle, wise, and understanding person as he tries to comfort them. Specifically, he understands why the events in the courtroom have made Dill physically sick.
Despite his gentle ways, the majority of the people of Maycomb reject Mr. Raymond because he lives with a black woman and the children they have together. His conduct, to them, is disgraceful and beyond understanding. Mr. Raymond, as he reveals to the children, pretends to be an alcoholic so that drinking will explain his lifestyle. When Scout protests that his dishonesty makes him seem "badder'n you are already," he explains his reasons:
It ain't honest but it's mighty helpful to folks. Secretly, Miss Finch, I'm not much of a drinker, but you see they could never, never understand that I live like I do because that's the way I want to live.
Mr. Raymond is willing to live with this lie in order to satisfy his neighbors' need to understand his lack of racism. He harms no one and wishes only to live in peace with his family.