Bear in mind that for most of the last hundred-and-something years, the psychological profession has laboured under the blank-slate assumption that human psychology is 100% learned and the human brain is somehow a general-purpose learning machine; in which case the identically of these unevolved blank slates makes perfect sense.
As recently as the 1980s I remember my schoolteachers telling me about instinct, and how ducklings knew immediately how to wander down to the water and start swimming; but that humans are different, we don’t have instincts. (Admittedly I’m sure my local primary school was not exactly on the leading edge of psychology research, but still...)