My issue comes with the fact that the men had not come to assassinate him, or harm him -- just to steal from him.
So this man has perhaps given his life to protect... His money. Which is the sad part.
I would stand by any attempt to protect the lives of innocents, or of the self, etc. It seems foolhardy to me, however, that a man with probably no military training, and a gung-ho attitude, took up a gun and perhaps got himself killed because people were stealing from his shop.