By now, the story of Navy Seal sniper Chris Kyle is familiar. He holds the record for the most confirmed kills, he wrote a book which led to a movie, and he was killed on a shooting range by a PTSD ex-Marine. There is also the troubling business regarding comments he made about Jesse Ventura. No doubt, he was a skillful killer. By all accounts, he displayed little emotion—possibly facilitated by the extreme distance from his targets. OK. Skillful killer, shows little emotion, and kills only the bad guys. But for the fact that these deaths are sanctioned by the...