Nobody thinks it's good for poisoned food to be sold. The libertarian argument that you're almost certainly mischaracterizing there is about the pandora's box

Nobody thinks it's good for poisoned food to be sold. The libertarian argument that you're almost certainly mischaracterizing there is about the pandora's box that is opened by allowing the government to decide what is or is not "poison" (which is of course an absurdly emotionally charged word picked by their opponents). Consider that some governments want to restrict sugary food on health grounds. Sugar isn't a poison but once you accept the principle that governments can ban companies from selling "poisoned" food, the definition of poison immediately comes under attack and sooner or later means almost nothing like what you'd expect.