- There is debate about whether drug policy specifically is the primary cause of the various increases in drug usage that we've seen around the US.

- There is debate about whether drug addiction in cities like Seattle merely correlates with homelessness/crime or whether it is the primary causal effect.

- And there are also debates on various metrics that people use that lead even people who do believe there is a causal effect to disagree with each other about how significant they think that causal effect is.

And some people do believe that it's all a straight causal effect and there aren't any complications and banning the drugs will solve the problem; but there's enough debate about it from enough serious researchers and a large enough number of inputs going into the system that I think it's slightly hand-wavy to describe the relationship between specific drug policies and crime like it's an established and widely agreed on fact rather than a highly contested debate among various researchers.