you get crap like this. And this.
An awful lot of this crap feeds on itself. You tell young kids that being a druggie and gangbanger is good, and that cops who are paid to enforce the rules are bad, you get kids who hate cops. When you're a cop and you keep running into this crap, especially from particular age/racial groups it affects how you treat those people precisely because you know they're the people most likely to present a danger to you. Which the assholes use as excuse to condemn the cops and call dirtbags who commit murder 'martyrs'.
And the 'progressives' and Race Warlord Poverty Pimps use it all to enhance their power. See 'activist dirtbags in Obama administration' and 'Al Sharpton' for examples.