It is not a problem that each person is different, it is a beauty of nature, to be celebrated, the diversity of God. It gives us opportunities to learn from these differences, and that's what we're attempting. Making blanket statements about "excessive" iodine, without defining what is excessive, is an indefinite statement that contributes nothing.
Its totally NOT a well known fact, these assertions you make, and if you do not wish to read more, I won't put a rubber band to your head to make you. That's the trouble these days with this generation, they don't read what has been elucidated long ago and instead read a couple short sentences and draw knee-jerk conclusions. Perfect for communistic rule, they can't think on their own. Its the eventuality of not having read enough, and the fluoride that makes the mind docile, and non-inquisitive. Lack of reading is a very bad thing, Hosea 4:6, if you care to read that :)