The theme of this comic is "Racism is the cause of hatred." This is demonstrated by how Lula was saying rude remarks about Jem and Scout attending a coloured church. This theme was also shown as Aunt Alexandra gets angry over Cal talking the children to a coloured church.
It's the same God ain't it?
Cal, can I come to see you sometimes?
You all were coming back from Calprnia's church that Sunday?
Well, I asked Calpurnia coming from church that day.
You may NOT
Yessum, and she promised I can go to her house some afternoon, Atticus, I'll go next Sunday if that's all right, can I?
I didn't ask you!
I'm sorry, Aunty
First, apologize to your aunt.
...You've got to do something about her, We don't need her anymore.