Actually, the biggest fundamental difference is that Atticus judges on the person. He sees what's on the inside. Aunt Alexandra only sees social structure and skin color. In her opinion if you're colored or born into a bad family, you're automatically less than those who are white or from wealthy families. I wouldn't call the Cunninghams trash. Not exactly. The kids were just responding to their environment. But even Atticus sees that they actually are. They lied about an innocent black man raping a girl to keep the secret of their incest safe. They torment and leave trash everywhere. People believe they will never rise above their station in life.