In chapter 2 why does meg think Mr. Jenkins's concern for her is an act?

The principle, Mr. Jenkins, tries to encourage Meg to do better in school, but after Meg is smug with him as well, he says coldly that her father is never coming home. Meg is sure that the postmistress, who saw her father's last letter a year ago, has spread news of his disappearance throughout the town.

In chapter 2 makes teacher and classmates make fun of her when she fails to answer questions response for aging out and being disrespectful to her teacher how does heat this develop a theme of the story