No, it doesn't. On what facts do you base your opinion that eight year olds have been smoking pot for the past 200 years?
Facts say that people cannot be separated from the seeking of pleasure, and facts say that marijuana may be perceived as a way to deliver that to oneself. (btw,
consumed may be a more accurate description, as smoking is only part of the story)
So no matter how sheltered a person may have lived his own life, it should become impossible to believe that every child in history has been successfully steered away from finding cannabis as a tool to deliver pleasure.
People, including children, were regularly treated with marijuana tinctures, as well, which was not an uncommon household item. Surely you wouldn't stake a claim to say that every child in history was successfully minded to the point where consumption was limited only at the direction of the parent. Right?
The unavoidable conclusion is that people, including children, have sought pleasure by consuming marijuana in the past.