i think it's 2 things:
marijuana use is so casual and enforcement is so lax (when i was at smoove there were people openly rolling up and lighting up 5 feet from the bouncers) - it's like making a song about drinking a couple of beers. hmm, wait, bearman...
there's no real cultural ties to the jamaican/rasta culture anymore outside those who consciously align themselves with it (jammer/dmz)
so smoking weed just means you like to get stoned - that's not badman!