I think the body is a much more biochemically complex system than we now know. Until good science is done to the point we have a complete understanding of how every hormone, nutrient, etc interacts with all others, I think it's fair to say that each individual will be slightly different from the next. I too ignore posts like that, since they're usually filled with those who have no hormonal fluctuations, and think it's therefore reasonable to dismiss anyone who does have non-average hormonal fluctuations.

That said, I do believe that weight loss is just calorie deficit. Establishing the right kind of deficit when one has thyroid issues is definitely a more intricate challenge than just "eat less." Making sure medicine is at the right dose, that you're getting all the right nutrients (so that medicine works as optimally as possible), not creating too big of a deficit (since that can further suppress thyroid function), finding the right balance of macros, making sure to rule out sensitivities that often go along with thyroid issues (soy, gluten, etc.). It's not simple to figure out the balance, and then rebalance again with significant changes in weight along the way.

I agree its not insulting and this person is uneducated about thyroid conditions or else they would not say such things. And yes weightloss and caloric deficit do help BUT that is not it as you all know.