Because at no point is the "mind" involved doing a step by step reduction of the problem. It doesn't do formal reasoning.
Humans usually don't either, but they can almost all do a form of it when required to. Either under the assistance of a teacher, or in extremis when they need to. We've all had the experience of being flustered, taking a deep breath, and then "working through" something. After spending time with GPT, etc it becomes clear they're not doing that.
It's not that reasoning comes intrinsic to all human thoughts -- we're far lazier than that -- but when we need to, we can usually do it.