On page 256 of chapter 23 (may vary a little depending on which version of the book you are reading), Aunt Alexandra boldy insults Walter Cunningham in attempt to prove her point as to why Scout cannot play with Walter. The selection reads as such:
She had said Indeed Not, but this time she would give her reasons: "But I want to play with Walter, Aunty, why can't I?"
She took off her glasses and stared at me. "I'll tell you why," she said. "Because--he--is--trash, that's why you can't play with him. I'll not have you around him, picking up his habits and learning Lord-knows-what. You're enough of a problem to your father as it is."
I don't know what I would have done, but Jem stopped me. He caught me by the shoulders, put his arm around me, and led me sobbing in fury to his bedroom. Atticus heard us and poked his head around the door. "'s all right, sir," Jem said gruffly, "'s not anything." Atticus went away.
Aunt Alexandra tells Scout that Walter Cunningham could not come over in Chapter 23 of "To Kill a Mockingbird" because he was "trash." She disapproves of the friendship between Scout and Walter due to social class differences.
Scout invites Walter Cunningham over for dinner, which angers Calpurnia because she feels that Scout is being disrespectful by not informing her beforehand. This incident disrupts the normal routines of the household and Calpurnia's expectations for Scout's behavior.
Aunt Alexandra forbids Scout from inviting Walter Cunningham to their house and tells her "'Don't be silly, Jean Louise,' said Aunt Alexandra. 'The thing is, you can scrub Walter Cunningham till her shines, you can put him in shoes and a new suit, but he'll never be like Jem. Besides, there's a drinking streak in that family a mile wide. Finch women aren't interested in that sort of people.'"
Aunt Alexandra decides to invite Walter Cunningham over for lunch to show Scout how to behave like a lady and to reinforce their social status. She believes it is important to teach Scout proper etiquette and to uphold the family's reputation. While her intentions are rooted in tradition and social norms, her actions overlook Walter's own dignity and worth as an individual.
Aunt Alexandra believes that the Cunningham family is not socially equal to the Finches, and she worries that their presence at the dinner would not be appropriate or conducive to Scout's upbringing. She is concerned with maintaining the family's reputation and feels that associating with the Cunninghams would be seen as beneath them.
She says that Walter is "trash" basically because he comes from a low-income family. Alexandra doesn't want scout playing with Walter Cunningham because he doesn't have very much money and doesn't want scout acting or playing how he does. She says that Walter is "Trash" and Scout shouldn't be hanging out with him.
Aunt Alexandra believes that the Cunningham family is a group of "fine folk" but is troubled by Walter Cunningham's presence at the Finch household due to his lower social status and economic circumstances. She urges Scout and Jem to distance themselves from the Cunningham family to maintain their social standing.
he is a shy lad, and his family is classified as low as it can get from Atticus's family. And he and his family are very poor. His behavior during lunch suggests that he is poor and has no money to eat or to pay back.
Aunt Alexandra objects to Scout inviting Walter Cunningham to their house because she sees the Cunninghams as lower-class and does not think they are suitable companions for the Finch family. She puts a lot of emphasis on social status and tries to instill these values in Scout.
Walter Cunningham ate lunch with Jem and Scout on their first day of school.
When the family goes to Aunt Alexandra's for Christmas, Scout hits Francis for calling Atticus a"nigger-lover". On Scout's first day of school she beats up Walter Cunningham because he made her look bad in front of their teacher. He didn't have lunch and Scout had to explain why. The teacher got made at Scout, so Scout got mad at Walter.
Scout had tried to come to Walter Cunningham's aid when the teacher did not understand why Walter had no lunch and why he refused money to buy lunch. But Scout cannot tell details of what she knows; she does say the teacher is making Walter feel ashamed. The teacher does not appreciate that comment! So she punishes Scout, and the class laughs. Scout beats up Walter because he got her in trouble.