Explain mama's plan for encouraging the other families to stop shopping at the wallace store

Mr. Jamison agrees to put up the credit for a group of black families to shop in Vicksburg and says that not all white Southerners feel the same way as the Grangers. Nonetheless, he reminds the Logans that the Wallace store is on Granger land and that Harland Granger lives in the past. Also, starting a boycott against the Wallace store is tantamount to saying that blacks and whites are equal by seeking to punish the Wallaces for the murder of a black man, a claim that may be dangerous in their town's current racial climate. Even if he cannot beat Granger or the Wallaces, Papa says that he wants his children to know he tried.