True enough, but there is a difference between taking the actual hormone(T3, T4), and taking a supplement which will boost production(KI). Kind of like the difference between test boosters and actual test injections. Sure, coming off test booster can cause temporary suppression, but nothing permanent. test, on the other hand, has the potential to cause permanent issues.
NOTE: I am not trying to start a discussion about steroid usage, I know test can be used for years with no ill side effects, depending on the person, the dosage, etc. Just making a comparison between the two situations.