Two things really resonate with me;

“Those who neither struggle against violence nor take part in it can no more be enslaved than water can be cut. They can be robbed, prevented from moving about, wounded or killed, but they cannot be enslaved: that is, made to act against their own reasonable will.” Leo Tolstoy

and

Nobody can force that process. It must come from within.

Violence begets violence. Take a look what is happening in today's world. What would happen if they stopped all their violent talk and actions? There would be no retaliation for perceived slights.

But you are right. You can not make some one change. The change must come from inside.