I found clue in your first sentence, Tofu (and Soy milk) as we know, is not a fermented soy product. Therefore it's a very powerful antinutrient, a pancreatic trypsin inhibitor, and if u have thyroid condition , it would worsen the condition . I think unfermented soy is the worst food that Vegan could consume. On the other hand, Fermented soy like tempeh and miso are fairly safe to be consumed especially it's cooked together with nutrient densed seafood.
Soy and Thyroid