Living in Ann Arbor, it is rather odd to hear about a protest getting violent in an otherwise open minded community that is as liberal and far left as San Francisco. Mob mentality.<p>Not the same context as the article, but as an example the protests can get rather fervent and loud: <a href="https://www.youtube.com/watch?v=-3orPtIGyUw" rel="nofollow">https://www.youtube.com/watch?v=-3orPtIGyUw</a>