Like MLK said, when people who are oppressed feel unheard by those in power, they become violent. This kind of shit has been going on for more than a century and non-violent protest has not made it stop. The cold, hard fact is that what progress that was made in the 60s, temporary as it may have been, was because of the combination of peaceful protest and the violence that happened in the riots as well as the threat of violence the white power structure saw coming from the Black Panthers and other militant leftist groups.. Those in power decided to make some temporary concessions in order to avoid constant civil war in the US between the govt. and the radical groups as well as black Americans in the cities.