You don't think that perhaps you have confused cause and effect?
Maybe cities with more social problems vote democrat, and nice safe areas vote republican?
There are few exceptions, but the cities that could be described as armpits in America have more or less gone full Democrat for the last 30 years. In those 30 years most of those cities have gone down down down, like Los Angeles (one mayor Riordan was R, rest D). Bradley was decent, but the last 3 Ds have been an absolute nightmare. Chicago and Detroit are prefect examples - they haven't fixed any underlaying problems.