Yeah, no chief or despot or king or prime minister ever took a nation or tribe to war with the explicit goal of reducing the number of young men in the populati

Yeah, no chief or despot or king or prime minister ever took a nation or tribe to war with the explicit goal of reducing the number of young men in the population. However, when you have a bunch of extra young men looking for something to do, as opposed to a shortage of same (i.e. not enough of them to do the things that need doing), the opportunity cost of going to war also goes down. So nations with a surplus of young men are more likely to go to war.