Maybe you missed my point. T'Kuvma's flashback showed all of the Klingon children were hairless, and presumably there wasn't a war going on at the time. The context of the scene is clearly meant to reinforce that DSC Klingons were supposed to be naturally hairless.
... or perhaps the children are forceably head shaved during a rite at a certain age, to prepare them for future battles.
The ones shown were all apparently about the same age.