It should not be a call to authority. The only thing that matters are the individual arguments he exposes in the books, not the fact he's not an expert.

And history has also shown some experts can be wrong when the paradigm change of new ideas is too big.

However, and I say this is particularly important: all refutations I have read about his work focus on some particular detail, they are of the type: 'this number is wrong'. Of course it can be, he's speculating. And that's the easy part to fix! Just change the number in his argument with the correct one. Be constructive.

But I have never read a refutation that says: 'this line of reasoning is wrong'.

In fact, his work has been cited as an inspiration for 'Sapiens', which is a current best seller and it follows the same modus operandi.