a good example is the work of daryl davis who managed to convince people to leave and denounce the kkk. i believe that the reason his approach worked is because those people believed that they were good people, and they left the kkk once they realized that they were actually wrong and prejudiced. if they had seen themselves as evil they would not have left, because doing so would have meant to stop being evil. but they left because they realized that being in the kkk was a contradiction to how they saw themselves.