Yeah. Excellent point. The free market hardliners' counterargument is that "well, it's not in companies' best financial interest to sell poisonous chocolate, so we can trust them not to do it to the best of their ability."

But that assumes consumers can tell when they're being poisoned. If a person drops dead immediately after eating a candy bar... sure, that's pretty obvious. But long-term harms can't be easily attributed to a single product.

The free market is a very very useful tool. So is government regulation. Both of them also are wholly inadequate on their own.