It does not surprise me that Chicago and Cook County do not make the list. The reason is the very high population of the city and the county, and this list is based on crime RATE. While there may be many crimes in terms of absolute numbers, because of the population, the crime rate is not that high. There are many safe areas and neighborhoods. I grew up in a neighborhood in the city of Chicago that was perfectly safe, with no crime whatsoever. The crime is concentrated in certain areas. As in any city, you gotta know your neighborhoods. Some are safe, some are dangerous, some are a little dicey.
BTW, today is Chicago's birthday! The city was incorporated on March 4, 1837.
I live in St. Louis now, but Chicago will always be my beloved hometown!