We've decided sugar is less harmful. It's also more useful in food than cocaine which would only be there to turn people into addicts. I'm inclined to think that if companies went around adding cocaine to food to make it more addictive the way they do with sugar society would be much worse, so it seems reasonable enough. If there's data somewhere that would suggest cocaine would be less harmful than sugar though I'd be open to taking a look at it and changing my mind.