"Different" stage - maybe, but... "not even considering" something that then happens on a huge scale is not a sign of being at a sufficiently advanced stage of

"Different" stage - maybe, but... "not even considering" something that then happens on a huge scale is not a sign of being at a sufficiently advanced stage of "civilization"/whatever you call it. Certainly not sufficiently advanced to be governing those people whose behavior one fails to predict. Also... if you're saying that "getting rid of the girls" is dumb ("indicative of lack of civilization"), as opposed to "bad" in some other way (say, immoral) - then, well, it might be much dumber for society than it is for individuals, depending on the specifics. (It depends on the various costs of raising a single child who's a boy vs raising a single child who is a girl. If you count on your child to be supporting the family with physical labor from a young age, for instance, a girl would be more costly to raise.) Pushing people to do something which makes sense for them individually but is a disaster for society as a whole is very common for rulers who're out to inflict as much good as possible upon their less-civilized subjects.