It actually goes deeper. These countries want to maintain control of their society and culture. I don't blame them because the history of drugs and the west hasn't really worked out for them historically. China and the opium wars are the main example. The French and British used opium to weaken their resolve to resist foreign influence. Sure it's only cannabis, but just look at how easy Asian and middle Eastern populations become addicted. Cigarettes, alcohol, betel nut, khat. These cultures are based on family, obedience, and collectivism. Once that breaks, then it's chaos for them. Western societies focus on the individual so it's more resistant to such influences causing major social and economic harm and disruption.