why was sam tutum tarred and feathered?

According to T.J., Sam Tatum was tarred and feathered because he allegedly called Mr. Jim Lee Barnett, the man who runs the Mercantile in Strawberry, a liar. T.J. says that Mr. Tatum told Mr. Barnett that he had not ordered all the things for which he had been charged, and when Mr. Barnett asserted that he had all the things Mr. Tatum had ordered written down, Mr. Tatum had asked to see the list. Mr. Barnett had insolently responded, "You callin' me a liar, boy?', to which question Mr. Tatum had replied, "Yessuh, I guess I is".

Even though Mr. Barnett most likely did not order all the things for which Sam Tatum had been charged, it was of little consequence that he was cheating his customer. What was important in the social climate of the times was that Mr. Tatum, who is black, had dared to stand up for himself and question a white man. The night men, or Ku Klux Klan, operated with impunity in the South during the years the story takes place, and they were very quick to take the law into their own hands whenever they felt the Negroes were "steppin' outa (their) place". In retaliation for his "uppity" behavior, the night men rode down to Mr. Tatum's place and "poured the blackest tar they could find all over him, then plastered him with chicken feathers" (Chapters 3-4).

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The Logan children were "relieved" to hear the news about Tatum becuase they had originally thought that the night riders (those responsible for Tatum's punishment) were out to avenge what the Logans had done to the school bus.