>> The  assumption seems to be that paleolithic man was as stupid as
>> neolithic.

Stupidity has nothing to do with it. It's all about what is available for survival. Paleolithic man did not "stupidly" decide to start cooking. Neolithic man did not "stupidly" start to raise grains. It just happened.

"Hmm, me cook today".
"Naw, you better not do that because it's against our nature".
"Me do it anyway! Then, tomorrow me try grains and beans. That sound fun".
"Whatever. Be stupid. Centuries from now you're going to regret it".

Seems like all of the psuedo-scientific dietary "philosophies" all have some sort of "golden age/out of Eden" hook.It's rampant with the Natural Hygiene spinoffs.