What is up with Japanese media's fascination with child soldiers

Why is this toddler in the army???

Such a tonal whiplash to get a scene like this after a cutscene where a rebel faction is doing a pogrom on an ethnic minority, with fleeing civilians being shot on-screen

I know the reason is that most Japanese media is aimed at the youth and all these school-age protagonists are meant to be relatable to the target audience. (They also romanticise the fuck out of high school over there for various reasons)

The older I get the weirder it feels watching cutesy anime kids going to literal war. Idk, maybe I'm overly sensitive or something. It also always has vaguely fascist undertones to me