You are right, it is important to have documents. The soldier obviously had passion for photography, judging by the aesthetics of the photos. I just got irritated by the asymmetry of the situation.
Are you're saying that engaging in war is somehow more just if the sides are equally matched?
If so, that strikes me as a strange criterion.
Not more just. But when the situation is more asymetrical the more farcical the powerful side's complaints of the weaker's perfidy. (Tons of examples. The most universally accepted were Germans killing 1-10 civilians in retaliation for dishonorable uninformed partisans)
"Pick on somebody your own size" isn't particularly bizarre.
War is absurd like that. This is why it's (usually) best avoided.