I believe it’s cultural relativism as David addresses the difference in moral codes.
The infanticide issue is independent to various cultures. David clearly states the essential cultural background and the undeniable consequences (the “ought to be”) without infanticide in arctic area. David didn’t take the ideas that whether infanticide is right or wrong on a universal level.
After our in-class discussion, my perspective shifts a bit since I am not sure about the specifics of David’s perspective, which requires his further elaboration.