"Primitive peoples were AP."
I think he coined the term because of people who say stuff like this.
FTR, I think that the above statement is completely untrue. There is massive diversity amongst pre-industrial and pre-agrarian societies. There remains a lot of diversity (some do not babywear, many do parent-led weaning, and many, many use corporal punishment). The defence (as per Dr. Sears) of certain attachment parenting practices as "primitive" (as if that were more "natural", i.e. less related to culture and more related to biology, presumably) is widespread. Logically, however, it's very weak.
I haven't read or checked out babywise--seems to be a waste of time.
However, I think that he's not far off-base about Dr. Sears' justification of AP, at least.
I personally hate the whole "primitive" thing. It's paternalistic, it's not accurate (it conflates natural, pre-industrial, and healthy), and it's misleading (because it implies that there is this culture of perfect parenting out there... or was... somewhere... that somehow, if you do everything right, you can have the perfect baby, which is bullcrap IMO).
So that is probably the ONLY thing Mr. Babywise and I agree on.