you mean fools who consider empirical evidence on every hand something that portends a possibility which a lot of people are denying on sheer "faith"??
There have been few cultures which have established a pattern of long-term Marijuana use, and maintained a strong economy or intellectual tradition. Morocco might be an example where a good study could amply show the results of long-term use.
There are some neighborhoods in California where a serious evaluation of the users and their habits might easily advance the concern I express. When ordinary people can accurately identify long-term usage by particular cognitive impairments, I'd say the only reason we don't have a competent study done scientifically that supports the same conclusion is a cultural aversion to making that conclusion.
Colorado data since legalization has a lot of people wanting to reverse legalization. A wave of dope DUIs might be police prejudice, but the accidents/deaths on the highways increase looks like a hard connection to use.
The user trend to progress into other drugs is another thing. While I don't know why people do what they do in that regard, crossing the MJ line is statistically linked to meth, cocaine, and other drugs. Let's see if OB can pull up something that runs against that correlation. . . .