You know, it's funny—I typically view "puritanical" as something Massachusetts is. In this case, I think it's more like simple dogma. Puritanism is based on morality, but our current view of drugs and crime (as a country) seems to be derived from the 60s-80s "war on drugs".

Instead, I see people just not trying to think about it. They become uncomfortable when the subject comes up. There aren't a lot of people making urgent, moral arguments against it—it really does seem like it's driven more by the momentum of law enforcement agencies attempting to justify their own excistance than anything else, and the rest of the country being complicity because they don't want to be labeled a hippy.