> For instance we don’t allow peddlers of snake oil to make whatever claims they desire The important word here is “peddlers”. We regulate the sale of medical

> For instance we don’t allow peddlers of snake oil to make whatever claims they desire The important word here is “peddlers”. We regulate the sale of medical products. (And advertising related to such a sale.) But we do not regulate who may join in the argument about (say) whether stress causes ulcers, or low-fat diets prevent heart attacks. The self-proclaimed experts have at various points in time been quite sure about these things. But thankfully their self-confidence did not result in a ban on people questioning the data.