Amazingly written for children, I guess. That's not a hit on you (ya old fogey), but simply stating the target audience of this story.

Of course people who previously had power want it back, but how will they do that if they will die out or get killed even before anyone re-invents guns? The entire premise of Tsukasa's fear is hogwash.

Nothing he says makes any sense, which in itself makes sense, because he is still a child.

EDIT:
Also, how did the muscle hogs not die after getting hit by a spear from glasses dude? I didn't get that at all.