This is a great question in such a diverse country as ours. In a word, subcultural theory is a topic within criminology that emerged from the University of Chicago. It was a approach to criminology that was more sociological in nature. It looked at groups and the culture of groups. At first, the Chicago school studied the social dynamics of gangs. Based on their research, they posited that certain subcultures have values and common sense notions that are more conducive to crime and other delinquent behaviors.
The proposed benefit if such an approach is twofold. First, it seeks to map out these subcultures and help them to break unwanted social behaviors. Second, it allows the government and other leaders to diagnose and help solve these social problems.
The basic assumption is that social problems can be found to stem from social reasons.