GP said that the motivation was racial, you said that the motivation was law and order. You can determine motivation better from future actions than from past context, and the actions showed a bias towards incarcerating minorities. If the intent was to prevent crime by reducing drug use, we should have seen similarly tough enforcement among white drug use, which we did not. You are falling into the common post hoc ergo propter hoc fallacy.

OP said that "criminality was the effect of the War on Drugs, not its cause." Maybe I am not understanding his point, but I took that to mean that crime was caused by the drug war, which cannot be reconciled with the data.

I meant that if you were to declare a similar War on Jaywalking, you'd see jaywalking rates skyrocket.

Ah, it was ambiguous (to me) what "The last point is unsupportable" referred to.