“traitor to the Negro people” for insisting on a nonviolent approach to the fight for equality, saying a movement based on sit-ins and Freedom Rides would never suffice.
Many said the same to Gandhi.
Gandhi's reasoning: the people who lead a revolution will later lead the country. So, only people trained in dialogue and compromise should lead the revolution. A little contradictory: such people are not revolutionaries. They need a principled leader.

