The notion of "primitive" cultures, societies, religions etc. has not been taken seriously by anthropologists for decades. His whole argument hinges on theories of cultural relativism from the late 19th and early 20th century.

So, yeah, I am going to dismiss arguments that are based on analogies to discredited ideas.

But where does he end up with the "primitive cultures"?

To me it looks like it was just imaginary concept used as a tool. Once you understand that development of cognitive abilities are related to environment and that they are not necessarily "levels", you can forget the whole idea of "primitive cultures".

This is prime example why one should sometimes "entertain a thought without accepting it".

The funny thing was that African tribesmen refusing to talk about things they've never seen before was actually some pretty clear thinking on the part of the Africans, confronting very confused thinking on the part of the anthropologists.