I don’t think we know enough about development in either children or chimps to be entirely confident in our conclusion. It is possible that some new discoveries will come out showing that empathy is somehow necessary for morality to blossom. But right now, as best we know, empathy is not like milk.
The qualification here is welcome - assuming these studies are from an honest and representative survey of the literature, I agree with this conclusion, and we can conditionally assert that empathy is a separate issue to the development of morality.
