You prevent kids from joining gangs by offering after-school programs, sports, mentoring, and positive engagement with adults. You intervene with gang members by offering alternatives and employment to help redirect their lives. You deal with areas of high gang crime activity with real community policing. We know what works.
Cold weather probably played a bigger role in bringing back the hat, but sadly, the hat common to New Jersey guidos, South Carolina rednecks, Idaho potato farmers and Los Angeles gang bangers is the ubiquitous 'tractor hat,' which is derived from the cheap baseball style cap with the adjustable plastic tab.
During my eleven years as a New York City public school teacher, I saw firsthand the impact that poverty has on the classroom. In low-income neighborhoods like Sunset Park, where I taught, students as young as five years old enter school affected by the stresses often created by poverty: domestic violence, drug abuse, gang activity.