re: Question: is there any other music around the world that celebrates violence?

Murder ballads, which are very much thought of as country/bluegrass/Appalachian have their roots in Europe and the British Isles.

One of the more well known, The Knoxville Girl (best known from the Louvin Brothers Tragic Songs of Life album) is based on an Irish ballad - The Wexford Girl - which was itself a derivative of the English ballad The Bloody Miller or Hanged I Shall Be. The English version was probably derived from even earlier poems.

There is actually a book called I Shot a Man in Reno: A History of Death by Murder, Suicide, Fire, Flood, Drugs, Disease and General Misadventure, as Related in Popular Song that traces some of the history.