you know i use to think along the same lines, but then i read about a 'situation' that made me think otherwise.
non-violent tactics may be a good starting point, but in some situations you need to intervene with actioin.
Example i was given -- Sam Harris was walking down the street in a forgin country, where he came upon a girl being harrased by a couple of thugs, and it looked pretty innevitable that she was going to be abducted/raped -- what have you. Now Harris went about intervening in a non-violent method. He played a dumb tourist and asked the thugs a question (i forget, i think it was like where is the train station, or how do you get to the museum) the question caught the thugs off guard, and the girl managed to run away in the confusioin.
Now his point was that yes he managed to save this one girl, but he didn't do anything to change the thugs attitude. In otherwords, the thugs are still out there and some other unfortunate person has now had their fate exchanged with that of the girl that got away. Had he intervened with violence and action, while he probably would have the shit kicked out of him, it would have sent a message of disaproval of the thugs actions.
He goes on to say In a world of non-violence one deranged psychopath could take out a whole population with a pearing kife.. While a bit extreme, i think it gets the point out there. We aught not resort to violence for all of our problems, but there are justifiable moments for violence.