1) Republicans exaggerate Chicago's problems for political gain, which has been the case since the 80's as pioneered by their saint, Ronald Reagan.
2) The media is complicit in this exaggeration in order to get a story.
3) Relaxed gun laws in Republican states, disproportionately Indiana, are responsible for a huge share of gun access in Chicago.
4) Chicago Democrats are not representative of the national party and the policies that have caused Chicago's problems would not be considered liberal/left-wing.