Brain is subset of computers, but llms are not subset of brains.
It could still turn out to be intractable without a better architecture, but the notion that it might not be impossible makes a lot of people very upset, and the only way it can be impossible even for just an LLM with a loop bolted on is if human brains can compute functions outside the Turing computable set.
> Any Turing complete system can emulate any other Turing complete system, and an LLM can trivially be made to execute a Turing machine if you put a loop around it
Wouldn't it be more efficient to erase the LLM and use underlying hardware as Turing complete system?
BTW. Turing test is just admission that we have now way of defining human level intelligence apart from "you'll know it when you see it".