i herd a diff story, it goes like this

in the early 20th century mexicans began to heavily migrate to the united states taking jobs for long hours and loooooow wages. in order to endure this harsh lifestyle they smoked weed. in the governments reasonable attempt to open jobs for white people (and to simply rid the country of mexicans) they labeld weed a mexican drug and since there were millions of bitter men in the US with their jobs taken by mexicans who immigrated here jumped on the band wagon and would do anything to rid the country of mexicans, including banning a popular medicince, weed. thus making the best plant on earth illegal