Lock and Load TV Gun Show

I've been watching the TV show, Lock and Load on the History Channel. I honestely respect the star of the show, R. Lee Emery, a Gunnery Sgt. (Honorary) in the Marine Corp. http://www.history.com/video.do?name=LockNLoad
However,the thing I cannot understand how he can act so happy and thrilled about the killing power of the guns he shows off. Many of those guns were used to kill Americans along with other people.
I guess I will never understand this, as I have never owned a gun and only shot a rifle and shot gun off a couple of times.