Atticus really shows his frustration here. He has lost the Tom Robinson case to bigotry and wilful ignorance. For once we see Atticus lashing out, in the calm way of Atticus has, at the white community of Macomb.
"You couldn't, but they could and did. The older you grow the more of it you'll see. The one place where a man ought to get a square deal is in a courtroom, be he any color of the rainbow, but people have a way of carrying their resentments right into a jury box. As you grow older, you'll see white men cheat black men every day of your life, but let me tell you something and don't you forget it-whenever a white man does that to a black man, no matter who he is, how rich he is, or how fine a family he comes from, that white man is trash."