The main purpose of the short story “Dry September” is an indictment of Southern culture, specially racism.  In the story, a young black man is murdered.  He is accused of attacking an elderly white woman, Miss Minnie, but is completely innocent.

A common theme in stories of racism in the American South, when a white woman accuses a black man of anything he is innocent until proven guilty.  The story is an indictment of Southern culture because of the following:

1. A white woman accuses a black man of a horrible crime just to get attention.  Miss Minnie is an old spinster just reaching for the spotlight.  She basks in the glory after her accusation and the murder, then returns to being unimportant.
2. Black men are assumed guilty.  Will Mays is murdered for attacking a white woman even though there is no proof that he did it.  He is guilty, and no one bothers to see if he is innocent.
3. Vigilante justice in the form of white mobs killing black men.  There is no trial.  A group of white men kill Mays as soon as he is accused.
4. Murder of a black man is commonly accepted.  No one in the community seems to care that the man might be innocent.  Although they begin to suspect nothing really happened, they are not disturbed by it and Miss Minnie is just upset she is no longer the center of attention.

As you can see, all of these things are terribly wrong and are only present in a terribly racist society.