Well, like someone said, he could have picked a city he knows well, like Milwaukee, or even a nameless city or made up one close to another, a la Metropolis and Gotham. He picked Chicago, so he is responsible for either researching (or coping with the criticism that he's getting it wrong). If he wants to put a real name on things, he should put in the necessary work to have it accurate, because real people live in real places.

Then, there's the issue that there's no reason why his Chicago should be lacking black people, or the other issues.