Your local law enforcement is only as good as the pool of people they are pulled from. This doesn't say anything about cops, judges, or lawyers. It has everything to do with Chicago. End of report
People, including former cops in those cities, have said similar things about Baltimore, NYC, LA, SF, etc, as well as many smaller towns (Ferguson, etc). It's not just a Chicago thing.
I strongly recommend The New Jim Crow by Michelle Alexander. It's an eye-opening book by a Stanford Law professor about the judicial system. Absolutely a must read.