> said that pot is the only drug that prevents him from doing any good work.

And this is where i suspect the big anti-pot push is coming from.

With alcohol you can go out for some beers after work, get buzzed, get up the next day with a nagging ache, and still come back to work.

With pot it is more likely that you go "fuck work!".

End result, pot is not good for business.

Looking across history, there is a whole mess or barely concealed agenda aimed at maintaining a workforce. Even the modern school system is perhaps put into place to produce and maintain a more useful workforce.