Tom Robinson is stereotyped as a threatening black man whose actions are motivated by anger and animalistic lust rather than intelligence and humanity. He is persecuted because of his race, not because of his actions. At this time in history, particularly in the South, black men were often accused of raping and attacking white women. The accusations against Tom Robinson were obviously false, yet he was convicted of the crime.
Similarly, Boo Radley is wrongly perceived by people who judge him based on his reclusive lifestyle. Boo is unfairly stereotyped, as is Tom Robinson because people rely solely on preconceived notions rather than personal impressions to form opinions and make judgments about him.