What has race got to do with it, first of all, and second of all, there are any number of things that people “look down on” - many of them are perfectly legal. People look down on spending all your money buying crap from those late night home shopping networks for example.
Did I say white, I should have said “Western Civilization”, and Cannabis as an intoxicant was looked down on in the West for thousands of years, that is why it’s use as an intoxicant never became common in Western Civilization.