So far I've been agreement with you on everything, except one: I do consider throwing a brick through a window to be violence. While it may not be as bad as hurting a person, it is still using force in a destructive way, which to me is violence. To use a stark example: when the Nazis threw bricks through the windows of Jewish-owned businesses on Kristallnacht, wasn't that violence?
Back to your point about overthrowing the system by force. Years ago, some American leftists were talking to Che Guevarra about the Cuban revolution, and they asked him if he thought the same thing could occur in the United States. Reportedly, he looked at them incredulously and said something like, "In the United States? Are you kidding?" I think his point was that in very advanced, industrialized countries with a significant middle class and a highly developed police infrastructure, armed revolution is bound to fail. I also think that if people are desperate enough, as in Cuba or Guatemala, they will take up arms, but to use an analogy: in Cuba, the frog was thrown into boiling water; in the United States, the frog is sitting in a slowly heating pot of water. See the difference?