To play the devil's advocate, based on the original posting by V in this thread, it does seem that fluoride does disrupt the thyroid gland, not at the actual gland, but whether the hormones, T3 and T4 get used and/or made properly. It seems that fluoride wrecks havoc with these hormones and also enzymes in general.
So, it will be a constant battle to rid of toxic materials or halogens. Yet, probably not overdo any supplement including Iodine or iodide. That threshold probably will be on an individual basis.