Are you asking why a side effect that is actually an entire health problem on its own, is a problem? Especially when there is a replacement that doesn’t cause it?
Side effects do not exist in isolation. High blood sugar is not a problem if it is solving a much bigger health issue, or is a lesser side effect than something more serious. If medication A causes high blood sugar but medication B has a chance of causing blood clots, medication A is an obvious choice. If a patient gets it in their head that their high blood sugar is a problem to solve, ChatGPT is going to reinforce that, whereas a doctor will have a much better understanding of the tradeoffs for that patient. The doctor version of the x/y problem.
Side effects do not exist in isolation. High blood sugar is not a problem if it is solving a much bigger health issue, or is a lesser side effect than something more serious. If medication A causes high blood sugar but medication B has a chance of causing blood clots, medication A is an obvious choice. If a patient gets it in their head that their high blood sugar is a problem to solve, ChatGPT is going to reinforce that, whereas a doctor will have a much better understanding of the tradeoffs for that patient. The doctor version of the x/y problem.