Some people aren't quite right in the head, Some people need to have a reason to be, a reason to stick through the hard times when everything around them has turned to shit, Some people like to have a reason for things that they don't understand, Some people need to fit in to a group, Some people like rigid structure in their lives, Some people listened to the voice in their head and it saved them from a tragedy and instead of thinking that they may have had good instincts or they were just lucky they attribute it to a higher power...
And also if you kill all of your enemies then of course the world will be more peaceful, Y'all are just looking at it from the wrong angle...