Posers running around like idiots is a symptom of a larger problem, namely the intrusion of the government into their family structure. That ain't rap's fault.
Rap's a willing accomplice, though, and an especially pernicious, cold-blooded, and exploitative one. Government's intrusion is certainly a large part of the problem, notably liberals' attempts to expunge God from every corner of the public square. Statistical morality ain't much to ground a society on.