Dogs are weapons of war, by your thesis.

Guns have one explicit purpose, and that's to kill.

When a 16 year old was found last weekend with a cache of guns that he bought, and was ready to mass shoot his school, that's not comparable to anything.

But it's a societal and cultural thing too. IEDs in schools could also happen like the Butler assassination attempt also had 'a truck filled with explosives in the parking lot'

So it's more a violent society rather than what weapon is used to carry out that endeavour.