Re: a senior moment here
Which one kills people and which one protects people?
Both offensive and defensive weapons can either kill people or protect people.
Offensive weapons can protect people by deterring an enemy attack (this is the concept of strategic deterrence, which every recognized nuclear power appears to support). They can also protect people by shortening an otherwise close-matched fight (this is an idea often invoked to excuse the nuclear-weapons use by the US in the 2nd world war).
Defensive weapons can kill people by removing or reducing the cost of retaliation after the attack, which makes a military intervention more palatable and more profitable to the attacker. The history of colonial wars of the past few centuries is full of relevant examples, so pick one.
As far as anybody knows, neither the norks' nuclear weapons nor the US BMD system have killed anybody not directly involved in their development so far, so the score here is nil-nil.
Let's hope it stays that way.