why does Jem offer a simplistic explanation about the cartoon of Atticus Finch on The Montgomery Advertiser rather than reveal the truth

The cartoon depicts Atticus as a boy rather than a man and pokes fun at his intellect and love of knowledge rather than his interest in the pretty girls around him. I don't think that Jem quite comprehends the context of the picture. It is really isolating Atticus as different from everybody else, the ignorance of everybody else, in the town.