Yeah - it is a good point about people reacting differently.
My sister had Hashimoto and she did diet and now her hormones are OK without any supplementation. She did it a few years ago - and every doctor she consulted (here in Poland) did not believe that a diet can do that. But I trust her and she did a regular checkups of thyroid hormones and and something that showed the immune reaction to track the progress and check what foods are good. I think now doctors are more open towards diets - but still I think no one would believe in a complete remission.
On the other hand you can find many similar first hand stories about every health condition with such weird beliefs.
It is a fascinating subject - and also a very high impact one: https://zby.medium.com/rational-patient-community-6d3617dffc...