[Daishiman]

There's a difference between allowing adults and children to consume things. Children have limited agency and we consider it a social duty to protect them from some of life's extremes until they're better capable of understanding the consequences of their actions.

You don't have to ban things not be authoritarian. Smart governments just price in externalities, which is why you slap tobacco and alcohol with extra taxes to offset the increased costs of health care and reduced adult lifetimes.