Why, in To Kill a Mockingbird, did Scout rub Walter Cunningham's nose in the dirt?
The incident occurs at the beginning of chapter three. Scout has had a bad first day at school, starting with Miss Caroline criticizing her father for helping her read. Scout was offended by this criticism and was quite upset about it. Jem's attempt at making her happy during their break didn't succeed much. The second incident happened when she started writing a note and Miss Caroline told her to stop, repeating her original injunction that Atticus should not teach her.
Miss Caroline is clearly annoyed with Scout, and when Walter Cunningham refused her generosity when she offered him money to buy lunch since he did not have any, Scout attempted to explain the Cunningham tradition of not accepting anything if they could not pay it back. Miss Cunningham had, by this time, obviously had enough of Scout and decided to punish her. She gave her six pats on the hand with her ruler and sent her to stand in the corner.
Scout, when second break came, was obviously upset that her defense of Walter Cunningham had culminated in the punishment she had been administered. This was, evidently, the cherry on top and she had to vent her frustration. She therefore held the innocent boy responsible for the suffering she had experienced and wanted vengeance. It is for this reason that she decided to rub "his nose in the dirt." When Jem intervened and stopped her bullying, she told him that Walter had made her "start off on the wrong foot."
Jem later magnanimously invites Walter over to their house for dinner, probably to make up for Scout's unfair abuse.
Jean Louise Finch, “Scout”, blames her mishaps that morning on Walter Cunningham. There was an incident when Miss Caroline, the school teacher, offered a quarter to Walter for lunch. Scout tried to explain to Miss Caroline that the Cunningham’s didn’t borrow money because they had no money to pay the debt back. Her explanation was lost on the teacher, and after several other issues Scout was involved in, caused her to get her hand smacked as punishment. These events, eventually lead to her transference towards Walter.
Scout rubbed Walter Cunningham's nose in the dirt because she blames him for getting in trouble on her first day at school.
When Scout's teacher, Miss Caroline, offers to give Walter lunch money because he doesn't have any, Scout explains that he won't be able to pay her back, and that he won't take the money. The Cunninghams are a proud family who refuse to take charity.
Miss Caroline becomes upset and frustrated with Scout's explanation and slaps her hand with a ruler. As a result, Scout rubs Walter's nose in the dirt for starting her off on the wrong foot with the teacher.
Because he was involved in her getting in trouble that day in school. Because he wouldn't explain himself, Scout did, only to get shamed in the process.