I'm not so sure that music is responsible for changing anyone's views - rather that it supports and justify's the views we already have. Did anyone purge themselves of racist feelings because they heard "We Shall Overcome"? Did anyone become a pacifist because they heard "Masters of War" or "The Universal Soldier" ? I doubt it. I do belive that music is a powerful medium - and it can give us new ways to look at our world. But I doubt that any large amounts of people made any radical changes in their belief system because if it.