It seems to be happening in many places. My family moved from one home because gangs took to roaming the alley whenever there would be an event at the nearby park. Then we moved again recently, in part because of destructively rowdy children and a pot-smoking, gangsta rap-singing neighbour.
I don't know if this is happening all over this country, but I think it has something to do with the "nastification" of America. In other words, American society is becoming nastier, and nastier, and nastier. And part of this nastiness is a seething contempt for others (often thanks to the filth spewed by various hate mongers of all stripes), a contempt that all too often results in crime.