Plus there is great pleasure in defeating your enemy - not something we would immediately look kindly on in polite company, but there nevertheless.
I think we once again have to separate pleasure as an ultimate goal, which we wouldn't generally pursue through a life of war, with the pleasures that can come through most any activity that is not always and every moment painful. And as much as we might want to call it that, many people do get great pleasure in war - at least when they are winning - just like boxers and others who fight for a living (all competitive sports?) Find it very exhilarating - again at least in some moments.