I've heard that a few times over the years. Americans don't know what war is like because we've never had to suffer it personally. Our soldiers always go somewhere else to fight.
So, I say this sounds like a perfect education. You kids like playing war? Lets go see what war really is because games & stories don't do it justice. Look it in the eyes and you won't treat it like a game anymore.
When they're adults, these kids will be able to look back and use this experience to make an informed decision on whether or not to fight in whatever conflict their country gets into. Sweden's next generation of decision makers will be better equipped because of the presence of these kid's experience.
If America did have a history of being trampled on, we'd be more nationalistic with a bigger military, and a long list of grievances to draw from and thirst for vengeance. I don't think anyone actually wants that.
Most Americans don't know what it's like to live in crime-ridden neighborhoods either, but if we all did, that does't mean our police would be less militarized, smaller, or kids would grow up and do less crime.
A least we are idealists. I know you want to think if we only knew war more personally we'd lose the will to fight, but that's not how it works. If every American soldier had to grow up with insecurity and death around every corner, things would be much worse when the time came to deploy them and that time would still come if you like it or not.
Do you suppose if your kid had his school blown up by some external threat, that would weigh against deciding to take up arms later in life? No.
If you want to show him someone else's blown up school and it makes you feel better, whatever. Thats like taking him past the bad side of town and saying don't join the police because THEY are fucked.