True, but I don't understand its relevance. I doubt any war has ever been fought in which a person in a state of mortal sin hasn't been killed. In fact, I'll bet millions have died in war in the same state of separation from God that Tookie was likely in.
You're probably right. Ideally, no one would die by violence ... but they do. And of course, although we can identify gravely sinful actions, no human being can know the state of another's soul. Only God can.
So we (as societies) have to make decisions the best we can. Do we not fight a war because we might kill someone, who will then go to Hell? Or if we don't fight a war, will a bunch of different people, our own citizens, be killed, and some of them go to Hell? Do we not execute an impenitent murderer, or do we give him the opportunity to kill others?