Where can we see the children’s loss of innocence and faith in others?

I might consider when Mama take the children to see Sam Tatum. Sam is a black man who lives on Jackson Road near Strawberry, he calls Mr. Barnett a liar after he denies cheating him. In retribution for this accusation, the white "night men" tar and feather Mr. Tatum. I think the children lose a lot of faith in humanity when they see this.