I don't disagree one bit with this. Of course we have to start with ourselves to affect real change. My question was more along the lines of potential illusory correlation and the notion that everything in the "system" is set up to discriminate against anyone other than whites. I am not saying there are not discrepancies and it definitely looks that way, but playing devil's advocate is it possible that the arrests and sentencing are not unfairly and purposely lop-sided but rather truly a larger issue among that demographic? GF answered it well with the comment about usage stats being roughly even across races (the only studies I could find still showed a larger proportion of blacks as users than whites, but there weren't big gaps, it was pretty close), yet the arrest and prosecution stats along with that are pretty huge gaps.
But so often it seems this kind of thing is used as an excuse, another way to absolve someone, individual or group, of responsibility for their actions, which is the single most damaging issue in our society today imo. We need the system to be more fair about it, and bring the proportions back in line, but it doesn't mean that we should swing the other way either and blame "the village" for the poor choices and actions of every child.