All this is regrettably unsimulationist of us. The fact is: we were forced to drop the Narutoverse's civilisation level to the very rough equivalent of the 12th century in order to make the tech, population numbers etc. make any kind of sense (reminder: Kishimoto didn't know the order of magnitude of the number of ninja in a village). Plus it became a death world. If we'd imported Early Middle Ages culture and ethics on top of that... well, the result just wouldn't be fun to write or play for anyone. Even for me, as it's too easy to be evil in a world where the majority of people are property and things like sexism and xenophobia are too ubiquitous to exist as concepts.
Well, if you're already going to do that, why take to the extreme for the sake of juxtaposition? With the exception of the small number of serious decision makers have everybody born with the ethics of a Federation Starfleet officer and watch them end up more neurotic than Kagome as the world breaks them.
In fact, that sounds like a good explanation for an increasing level of personality disorder and unhealthy coping mechanisms with rank.