One issue is , there is a small fraction of the population with un-diagnosed mental disease who go around blabbing and encouraging others to mass-dose themselves with all sorts of things, like iodine. Those types of people are the reason why medicine practice needs to be licensed, otherwise, those blabbermouths would entice others into harming themselves. Fortunately, many are not so gullible. Its the gullible ones who need protection from the blabbermouths who often, don't even have a high-school level of understanding of what even a "halogen" is.