(The use of) anything that quickly alters one's mental state through normal use should be illegal.
Billions of people can take a sip or more of an alcoholic beverage and not get drunk, but 1 hit off a pot blunt provides an immediate high to the average person.
In other words: getting high or drunk should be illegal.
I frequently heard the story of my mother's first taste of wine. Back in her day, no one was surprised if a woman hadn't drunk alcohol because the culture frowned on women drinking and there was never a lack of things to quench one's thirst so most women didn't care. My father took her on a date to a nice restaurant and ordered wine. My mother didn't want to seem ungrateful, and being of age and having never talked about drinking alcohol since the subject had never come up, she thought this would be a good time to try it. Well, after the first glass she was unable to stand. Of course later she drank socially with a normal tolerance.
Are you sure a person cannot have a normal tolerance for other drugs the same way? I'll admit since I'm user I don't know. This isn't to say that drugs are good, but that you need to be careful about the message you send. If it turns out that a normal tolerance can easily be achieved, anyone who has achieved it will scoff at your message and you will have made things worse, not better.