The racial aspects of temperance (alcohol prohibition) and weed prohibition goes back about 120 to 140 years ago when black and latino migrant workers in the Deep South toiled together in agricultural production. Mexicans and central Americans migrating into the U.S. back then brought with them their drug of choice -- cannabis. See Martin Lee's 2013 book,
Smoke Signals: A Social History of Marijuana. He documents these racial fears that blacks rubbing elbows with latino migrant workers would soon take up pot smoking, which turned blacks into "hypersexualized beasts."
J. Edgar Hoover, first director of the Bureau of Investigation, routinely rounded up jazz artists, almost all of them were black, for smoking weed. He feared that blacks and weed use would inevitably lead to a communist takeover of the U.S. government.
Richard Nixon, who created the contemporary drug war with Elvis Presley's endorsement, considered pot smokers and black freedom struggle activists (as well as anti-war hippies) to be "scumbags," and his whole "law and order" rhetoric was designed to use fears of illegal drugs to round up black people and throw them in jail.
http://www.alternet.org/drugs/our-drug-laws-have-always-been-racist-americas-ugly-history-prohibition-tool-oppress
Today, sentencing disparities are highly racialized. Non-whites convicted of pot possession or sale are given far lengthier prison sentences while many white offenders convicted of the same crimes are given rehab as a sentence and suspended sentences or probation.
https://www.aclu.org/feature/war-marijuana-black-and-white
It's easy to deny the racial implications associated with pot criminalization, but that's not the reality of the situation. Race is directly connected to pot's checkered history in the United States. To say otherwise is to be ignorant of the facts.