Really. There were peaceful protests that were successful. But there were also many violent ones. Violence can and has changed many things.
I don't like violence, but I like those wrong etaist pacifist statements even less.
Edit: Or are you talking only about this specific situation and this is your opinion? Then nevermind, could very well be true here.
In essence violence justifies counter-violence. The more the angry protesters threaten or attack the police, the less "wrong" the current response looks. Non-violence tries to starve the legitimization of excessive force.
This militarization is not a good idea and should be limited or abandoned. But "riots" are hardly making a point against military gear.
In the near east there is a similar problem. There is so much violence going on from both sides, that people can sympathize with cruelties from both sides.
Colonists had to murder plenty of police and military.
I'll just go ahead and leave this here: http://en.wikipedia.org/wiki/Robert_F._Kennedy's_speech_on_t...
The legacy of people who believed that violence is never justified, never necessary and can be overcome with compassion.