Is Jem immune from the disease of racism?

Jem is not racist, though he is certainly not immune to its effects. Jem's beliefs that Tom's trial will be based upon the truth and evidence is incorrect, and as a result, he is unable to talk about the event because of his disappointment and disillsionment.

"Jem was suddenly furious. He leaped off the bed, grabbed me by the collar and shook me. 'I never wanta hear about that courthouse again, ever, ever, you hear me? You hear me? Don't you ever say one word to me about it again, you hear? Now go on!'" (247).