Much ado about nothing. One puff when it was offered to him. So what? He was much more affected by the whiskey, but curiously no one has a problem with that. He even made it clear that he doesn't use weed because he feels it affects his productivity. All you're upset about is a nonsensical stigma.
Furthermore, the actual content of the interview was interesting.
Stop trying to turn Elon into a yet another fake CEO.