> And crime statistics are directly dependent on the policing and prosecution of crime--they don't reflect the objective reality of crime, they reflect the outcomes of an imperfect system that detects and punishes crime.

That's true for drug use crimes and to a lesser extend drug selling crimes, which make up way too many of the crimes prosecuted. Similarly for other crimes where police have a large amount of discretion to decide whether or not to arrest someone.

However there are also big differences in crime rates by race for murder. It's very hard to dismiss this as the result of how murder is policed. Police generally have much less discretion in how to deal with murder.