I prefer to work the other way around. That is, accept that a lot of human speech (and text) is generated via similar mechanisms to the ones that drive LLMs, but note that there is another kind of behavior - reasoning - which seems to be distinct.

I think you need understanding to reason, but you don't need reasoning to understand. A child understands how to catch a ball without reasoning about forces, air resistance, gravity, etc.

I think LLMs understand without reasoning. They've built a large associative network of concepts (a kind of understanding), but we don't yet have a good handle on the process of reasoning using that network.