The store bought PB cookies are probably a room temp paste, dehydrated then flash browned, not actually cooked the way homemade would be. Such formulating twchnique will not kill the bacteria inside the paste but would reduce number in a cookie until it had time to flourish on the shelf.
You are probably right, didn’t know they used a paste. I used to like those cheese crackers w/pb, and that looks like it could be some pasty concoction, don’t know diddley about the mfg process of pb.
Are all store bought cookies made that way?