You remind me of a guy who used to call himself "Proud Surrey" at the National Post.  (He was also known as "Proudly Surly".)  Your claim misses out on right-wing violence in Europe, burnings of black churches, economic violence (which I imagine you don't believe in) as perpetuated by the Chicago School, the occasional murder of a doctor who provides abortions, and the fact that in North America, there is little for the right to protest; they are largely running the show.
The car-burning crowd generally consists of the Black Bloc thugs, who are anarchists, not leftists.  The overwhelming majority of people involved in recent protests have behaved well.  I know -- I've been in some.