Seriously, if you're a celeb over there and caught smoking a joint, your career is basically over.
Even the infamously prudish U.S. is more accepting of it.
I'm guessing it's a leftover of U.S, imperialism, like how all their porn is still censored.
My friend saw Sleep and Boris play in Japan and they said it was so weird seeing Sleep in a room that doesn't smell like weed.