Because there is a fucking difference between black-on-black crime and some white-on-black crime. Black-on-black crime is just usually crime (like white-on-white crime), "this guy made me angry so I'm going to assault him" or "this person has something I want so I'll steal it." But with some instances of white-on-black crime are a hate crime, because "some people have a characteristic assigned to them at birth and I don't like that characteristic so I'm going to go shoot up a church." Do you see how there is a difference in these types of crime? One is just normal criminal activity, and the other is driven by an fear, or ignorance, or hatred of an uncontrollable characteristic that someone has. It's discrimination, it's racism, it's a hate crime, and it's terrorism. That's why it receives different attention.

As for Chicago, do you know how a lot of guns get into those big cities in the north? Chicago, NYC? They travel up there through what is called the "Iron Pipeline," where guns are brought into these cities after being purchased in states with few gun restrictions. According to data in 2011, 90% of all guns used to commit crimes in NYC were purchased in other states. 320 of those guns came from Virginia alone, where no background checks are required on private sales.

When it comes to gun restrictions in the U.S., hardly anyone is talking about completely banning guns. Just implementing systems to make sure that people who really have no business owning one won't get a hold of any. Background checks, mental health evaluations, mandatory safety training. These are simple reforms America could institute to reduce the staggeringly high gun violence rate the U.S. has. You say people who are engaged in illegal activities won't care about restrictions, but even the simplest systems can be instituted to ensure that weapons aren't allowed to fall into the hands of those who shouldn't be near a gun, and that's all that matters.