Seaweed/kelp is a “food” if eaten in its original state and not dissected. So, why not eat a food that contains iodine in proper combination? We often choose a food for its high content of a given vitamin or mineral, don’t we? And yes, there is unavoidable toxic garbage in anything we eat.
I think it was Schulze who spoke of the Vit C craze years ago. It first came out as pure C. Later they found it worked better with rutin… then ???. Schulze said “Why not eat an orange? It has C plus all the stuff body needs to utilize it plus who knows what other unknown compounds yet to be discovered. My point is: Why not eat kelp in moderation?