I must agree that this article is rather flawed. No where does it even acknowledge that persons who break one law, i.e. smoking pot, would also tend to be people who would also break other laws as well.
Before I go further I must emphasize that does not mean to imply that all pot smokers are criminals in general. Just that the natural tendency of people who defy one law will many times ignore others as well.
I also wonder if the states that have legalized Marijuana have also lifted the ban on industrial hemp. Which incidentally is the material used to make the paper the constitution is written on and many of the continental congress grew.