Why would we exclude child mortality? It isn't clear to me that isn't an indirect product of culture any more that any other longevity indicator. Blue zones se

Why would we exclude child mortality? It isn't clear to me that isn't an indirect product of culture any more that any other longevity indicator. Blue zones seems somewhat ambiguous but if I'm understanding correctly, they are small areas of people who live more traditionally surrounded by mostly modern people? Seems like by definition those zones are made up of cherry picked people and it's unclear to me that those aren't just outliers.