What I meant is supplementing for medicinal reasons, not nutritional reasons. Obviously people like vegans are going to have to continually supplement with B12, or people not getting enough sunlight will probably have to supplement with Vit D.
I'm talking about taking high-doses of a nutrient to produce a medicinal effect. If taking high doses of a nutrient makes a person's symptoms go away and if they stop taking that high-dose and their symptoms don't come back then taking that nutrient at high dose produced a cure.
If their symptoms come back as soon, or relatively soon after stopping the nutrient at high-dose, then the high-dosing of that nutrient was just producing a bandaid effect.
If the Iodine forum is anything like the other forums here, then what I think is happening is these people are coming in calorie-restricted and the high-dose of Iodine is producing a stimulant effect (as you admitted above it does) and these people are mistakenly thinking the Iodine was their missing link to getting their health back when, in fact, their are just bandaiding themselves.