I have to disagree with the previous post, since Aunt Alexandra plainly told Scout that her friend, Walter, was not welcome in the Finch home

"Because--he--is--trash, that's why you can't play with him."

Aunt Alexandra obviously does not agree with Jem's four levels of social status in Maycomb. According to Jem,

"... there are four kinds of folks in the world. There's the ordinary kind like us and the neighbors, there's the kind like the Cunninghams out in the woods, the kind like the Ewells down at the dump, and the Negroes."

Aunt Alexandra seems to lump all of the poor people of Maycomb together, and she sees little difference between the Cunninghams and the Ewells. Alexandra is obsessed with her family heritage, and the Cunninghams were long known for being ne'er-do-wells.

... they hung around the barbershop; they rode the bus to Abbottsville on Sundays and went to the picture show; they attended dances at the county's riverside gambling hell, the Dew-Drop Inn & Fishing Camp; they experimented with stumphole whiskey.

Such people were not fit friends for a Finch, Atticus' sister reasoned.