I believe that the main reason was for "gold"
i can't quite see the picture.
Yes, there is a theme on social justice. The author is persuading the reader through writing. She is using the children to introduce topics to the novel that might seem blunt and opinionated if it came from an adult or if the author said it directly. The setting of the story helps show that in a small town it is very easy for a certain group of people or person to be looked down upon by others.
