As Kevin has said, drug abuse (or definition of a drug), is subjective. A Rastafarian would never consider marijuana a "drug", to him it is a sacrament, and is only one aspect of a way of life. Marijuana has been of very real and substantial benefit to many people. (unlike drugs such as alcohol)
By the way the guy on the beach with dreadlocks, eating jerk chicken, or asking you to buy him a beer, is not a Rastafarian. Just because a person has dreadlocks, or says he is a Rasta doesn't make it so. I doubt many of us have even spoken with a Rastafarian. No Rastafarian would promote drug abuse. (I know I am probably preaching to the choir
I hope Snoop is sincere in what he says, his actions will speak louder than words.