Alcohol would be a good example, as would be unhealthy foods from the restaurant industry and food supply chain. But restrictions to drugs are made on an ad-hoc basis and not from a general principle.

While not banned, a lot of countries restricted television advertising of unhealthy food to children during childrens programming. I dont know how effective this was/is, but I suspect it's been erroded by new marketing channels(internet etc) anyway.

A better analogy is – should beverage companies get into trouble if minors routinely consume their products?