Quote: I've never heard that blacks did a lot of marijuana. Crack, yes. Jail, yes. Fatherless children, yes. But, marijuana? That's the one stereotype I've never heard about black people, till now. Thanks Fatman.
What I heard could be apocryphal.
It was the jazz era, the 20s & 30s. Allegedly it was big with black jazz musicians who allegedly began to popularize it with white youth who were into jazz culture in perhaps similar ways to "wiggers" and hip-hop/rap in our time.
Oddly, the theory was that pot made people violent. Maybe the residue of the "hashish/assassin" thing from the Crusades [our word assassin is derived from the Arabic for "eater of hashish"].
There were fears of black jazz thugs with razors run amok. [for some reason the "razor" was the stereotype weapon of choice for the "colored", if you will].
I recall seeing a quote from a politician or maybe a newspaper editorial about pot given blacks the courage to look white women in the eye, or something to that effect.
So, it's hopped-up black men, violent & sexually aroused in the presence of young waiting-to-be-deflowered-when-drugged white women ... all to the soundtrack of that pernicious jazz.
You get all those elements in "Reefer Madness," where pot leads to violence when one guy tries to drug the "virgin" girl, they've got the piano going with jazz [which was a bit of code for blacks, like rock & roll was in the 50's].
The Mexican thing makes alot of sense, but there weren't many of them here. So, maybe what I heard was about why NY made it illegal.
Maybe every area has their own anti-pot Genesis.
When I worked in the internet world, this Mormon guy I knew said that the main reason it was banned was that run-of-the-mill Mormons were getting high and it pissed off the elders. [You know, his theory fits well with the Mexican theory ... maybe its a side reason, too. No idea.]