It doesn't mean we can accurately simulate the brain by swapping its source of nondeterminism with any other PRNG or TRNG. It might just so happen that to simulate ingenuity you have to simulate the universe first.
If the brain exceeds the Turing computable, then all bets are off, but we have no evidence to suggest it does, nor that doing so is possible. This was in fact my original argument.
The only viable counter to my argument is demonstrating that there are computable functions outside the Turing computable, and that humans can compute them.