So let's say we have a protest on police violence, something some people here like to make abundantly clear they don't really care about, nor do they feel affected by. How can they claim that the message of the protest is invalidated by fringe violence if they didn't care about the message to begin with?
If a group of people feels unsafe or insecure in their community due to perceived police violent, protesting seems to be a pretty valid way of letting your feelings be known. Plus that, and protesting is a largely American thing to begin with.