: Non-violence is about TACTICS and RESOLVE, not morality.
As I see it, those who have a monopoly on violence possess, by default, a monopoly on morality. After all, only those already enjoying positions of power want peace (i.e. no challenge to their power). To seek power is to know its absence. Hence the need for violence in deciding which class IS to have power.
Once communists take power from the capitalists, communists will be all for peace! As a matter of fact, communists will outlaw violence the moment they have taken power from the capitalists. It is to expected, however, that once classes resolve into only ONE class (workers) and the means of production are made public, there will be fewer confrontations and less to protect than before.