When we consider the sacramentality of the world, the physical reality with which we all contend is sacramental in the sense that it has the power to induce the divine virtues and therefore our transfiguration if we are attentive to its restraints and how we should respond. So, as a more trivial example, to get from point A to B while respecting the limitations of my corporeality, I must have at least a modicum of patience and humility to physically travel a distance without ranting about how long it's taking and how I'm too important. While this is a common minor disturbance, the more strenuous and difficult the situation we're in, the more we must learn to cooperate with divine grace to cultivate the divine virtues that will help us cope and harmonize with these physical restraints. This is how we can say, "Glory to God for all things!"
But violence is anti-sacrament because instead of allowing a difficult situation and the accompanying physical constraints of time and space to transform us or instead of engaging in a creative act of transformation and restoration (much like beating swords into ploughshares), violence destroys that which was potentially transformative and salvific out of frustration, fear, and little foresight. It hastily and convulsively removes the corporeal barrier for the sake of temporary gratification without thinking long-term rather than letting this corporeal barrier and difficult situation teach and transform us. It’s a missed opportunity. This is how violence is anti-sacrament.
But why does this matter? —Violence is an attempt to futilely control the physical world around us (including humans) rather than allow the physical world to “control” us by revealing our limitations and encouraging us to adapt by cultivating the divine virtues that allow us to cope and harmonize with the physical world around us. Nonviolence as sacrament is salvific.