Taboos around violence for political are one of the crucial building blocks for a functioning democracy. If those taboos are broken, even for a good cause, you set a precedence that violence works. And the next cause won’t be as good. One only has to look at the lessons of the Roman Revolution that started with the murder of Grachus, and ended with an Emperor who everyone acclaimed as they were so tired of the bloodshed.
I imagine that many people on those current protests believe they aren't in one either (or, at least, if one exists they are cast out of it). I'm in no position to judge if they are right, but on the case they are not, violence is no means to do a democratic protest.