Overly simplistic statement to complex and dynamic problem:
Violence is not an answer, nor a means to an answer.
Violence is an outcome when an answer is not found, and people cannot endure any longer.
Some problems have no solution; When there is a worldview that completely ostracizes another group and their world view, there cannot be a mutually acceptable answer. (See the middle east, et al.) All that happens is that both sides get fed up with each other, and the rate of new atrocity greatly outpaces the rate of healing and progress toward mutual understanding and acceptance. Eventually, even the initial cause of conflict is forgotten, and all that remains is the poisonous contempt, outrage, and mutual exclusionism. (See eg, Hatfields vs McCoys)
Which side of the Hatfield vs McCoy feud were the victims? Which side the aggressors?
At some point, when violence gets employed, there are no victims anymore. Just two sets of aggressors, taking everyone else along with them.
Allowing a situation to fester, to the point where violence becomes inevitable, is how you fail to find a solution. There might be some salvation if caught early, but after a certain point, history suggests that only allowing that fire to burn out really gets rid of it.
The protesters need to ask themselves a very important question: Am I being part of a solution, by choosing to act this way?
This is a very important question, and one they MUST ask themselves, if they are going to try to claim that mantle; Violence is never a solution. It is a symptom of the problem getting worse.