Fundamentalism and Violence

I've long been preoccupied by the link between fundamentalism and violence.  My father's assassination by a fundamentalist cult first captured my interest.  Then a series of violent crimes committed by people linked to polygamous fundamentalist groups underscored the connection: Besides my father, at least a dozen people were murdered by Ervil LeBaron's Church of the Lamb of God, including Ervil's own brother, Joel.  Then an aspiring polygamist who believed himself to be God incarnate, David Longo, killed himself and left instructions with his wife to do the same; she forced their seven children off the balcony of a downtown Salt Lake City hotel, holding the baby in her arms as she jumped to her own death.  Ronald and Don Lafferty slashed the throat of their sister-in-law Brenda Lafferty, and her baby daughter, because she wouldn't go along with polygamy.  Polygamist John Singer refused to pay his water bill, his grounds being that the laws of God outstrip the laws of the state in importance; this and other conflicts with local law enforcement led to his being killed by a policeman's bullet.  Ten years later, Singer's son-in-law, Adam Swapp, retaliated by firebombing an LDS stake center in Marion, Utah; during the ensuing gun battle, a police officer named Fred Haus was killed, and a member of the Singer family was paralyzed from the waist down. Then polygamist Jim Harmston organized followers into a fundamentalist militia currently holed up near Manti, Utah, a group reminiscent of the Branch Davidians of Waco, Texas.  

Given this correlation between fundamentalism and violence, we can be grateful that no one was killed during the raid on the YFZ Ranch, although some would argue that the state of Texas perpetrated violence on the children by depriving them of their mothers.  (Others would argue that the state would have been negligent had they not invaded the ranch and rounded up the children.) I'll delve deeper into this issue of fundamentalism and violence.  It has become a phenomenon that shapes our world. Why does fundamentalism so often lead to violence? I welcome your thoughts and observations.