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.
We have a democracy. People have opportunities to vote. Police policy is decided largely at the local level, so individual votes are powerful. Imagine if even 10% of protesters voted in their local elections...
You can also see dirty tricks at local council meetings, where those in authority abuse the meeting’s rules of order to quickly shut down anyone speaking up about problems that those in authority don’t want addressed.
If you want to change the way things are inside the system vote, organize, protest. But actually seeking to overthrow the government is opening a whole can of very, very bad things.