If ChatGPT is a) usually used with a setting that makes it non-deterministic and b) for whatever reason, is also non-deterministic when that setting is not used

If ChatGPT is a) usually used with a setting that makes it non-deterministic and b) for whatever reason, is also non-deterministic when that setting is not used... then why did you comment as if the person calling it a non-deterministic LLM was incorrect? They didn't claim all LLMs are, or must be, non-deterministic, just that it's a problem with this one that is.