There are many different reasons for gun control in some of the bigger northern cities. Some of it was from a culture clash where people from down South, who are extremely friendly but sometimes react to serious insults with lethal force, moved up north where people aren't as overtly friendly to strangers and like to hurl insults all day. The simplest solution was to disarm all the blacks....
Just a bit of stereotyping, don't you think? Northerners may (or may not) tend not to be as friendly as southerners, but the vast majority don't "hurl insults all day." In fact, I don't know anyone who hurls insults all day. And, yes, I grew up in the north and still visit family and friends there.