EDIT: And a excerpt from the book "Rise of the Warrior Cop" from last summer: http://www.salon.com/2013/07/07/%E2%80%9Cwhy_did_you_shoot_m...
And Slate has a current piece on the phenomenon specifically in reference to Ferguson: http://www.slate.com/articles/news_and_politics/politics/201...
http://cdn1.vox-cdn.com/uploads/chorus_image/image/36894460/...
But when the reaction of the police to spraying "Fuck the police" on a mailbox is that six of them charge you with rifles aimed at you, that seems like a pretty clear justification of the sentiment.
Police: "Umff flumfff urgffff fruffu hufff froof!"
Youth: "I want to comply with your orders. I am not violent. I am not resisting. I can't hear y..."
Police: "UMFF FLUMFF URGFFFF FRUFFU HUFFF FROOF!!"