How does Jem respond to the news that one of the jurors was a Cunningham and that he had initially moved to acquit Tom?

In Chapter 23 of the novel, Jem's initial response is surprise since it was a Cunningham who led the lynch mob and who had tried to kill Atticus the night before in front of the jail. However, it becomes clear that his initial surprise gives way to confusion when he says, "One minute they're tryin' to kill him and the next they're tryin' to turn him loose . . . I'll never understand those folks...

In Chapter 23 of the novel, Jem's initial response is surprise since it was a Cunningham who led the lynch mob and who had tried to kill Atticus the night before in front of the jail. However, it becomes clear that his initial surprise gives way to confusion when he says, "One minute they're tryin' to kill him and the next they're tryin' to turn him loose . . . I'll never understand those folks as long as I live."

Jem's words reflect his youthful and simplistic judgement of people as all good or all bad. The conversation he has with Atticus about the Cunningham on the jury initially voting to acquit Tom forces Jem to realize that people are not always easy to label. Atticus explains that the Cunninghams have a strong sense of right and wrong. When they thought Tom was wrong, they sought to lynch him as an act of justice. However, after hearing the facts of the case, the Cunningham on the jury votes his conscious (at least for a while) showing he didn't believe the girl or her father to be of good moral character.