Aunt Alexandra considers a person who comes from an established family a good person.
The battle between Scout and Aunt Alexandra is not just over wearing overalls versus dresses. Atticus do has raised his children to care about others, and to judge people based on what they do and not who their family is.
Somewhere, I had received the impression that Fine Folks were people who did the best they could with the sense they had, but Aunt Alexandra was of the opinion, obliquely expressed, that the longer a family had been squatting on one patch of land the finer it was. (ch 13)
Aunt Alexandra tries to get Atticus to teach his kids the “facts of life,” about how they have “gentle breeding.” Basically, she means they are from a rich, important, established family. This is not as important to Atticus. He only cares about making sure his children have empathy and morals. He wants them to be good people and care about others.
Scout does not agree with her aunt on this account. She does not consider the Cunninghams trash, for example, just because they are poor. They are good people, and friends, and that is what matters.