Selenium deficiency decreases the activity of selenoproteins, including glutathione peroxidases, which can lead to raised concentrations of hydrogen peroxide and thus promote inflammation and disease. Such environmental pollutants as smoke, polychlorinated biphenyls, solvents and metals have been implicated in the autoimmune process and inflammation. Environmental factors have not yet, however, been sufficiently investigated to clarify their roles in pathogenesis, and there is a need to assess their effects on development of the autoimmune process and the mechanisms of their interactions with susceptibility genes.
they appear to be stating that selenium deficiency and toxicity are a root cause but they haven't actually got round to assessing it? Not very professional of them is it.
I could say taking 3mg of Iodine a day caused all my problems, but it didn't - my lack of preparing the body first did, and you will find everyone with bad reactions to Iodine are toxic and have poor elimination routes. I've spent a year getting rid of heavy metals and improving mineral and vitamin status etc, and I see no reason why anyone would trigger hashimotos (which I have) from taking Iodine unless they haven't cleaned up first and even then the hashimotos would already be there in the background. Iodine will just expose a problem that was already there, to use your phrase it is only the messenger.