This is my take on it. I have read the bio's of many angry people , like Glenn Beck, and Karl Rove, people who do their utmost to do cruel things.
When grief is not resolved, when one does not go through the whole process, in time, the pain one is trying to push down, eventually comes out warped and angry.
here are some examples:
Personal life
Currently a resident of New Canaan, Conn., Beck was born in Mount Vernon, Washington, Glenn Beck was raised a Roman Catholic. His early life was pitted with tragedies. His mother and one of his brothers-in-law committed suicide, and a sibling had a fatal heart attack
http://en.wikipedia.org/wiki/Glenn_BeckIn December 1969, the man Rove had known as his father left the family, and divorced Rove's mother soon afterward; it later became known he was homosexual.<6><7> After his parents' divorce, Rove learned from his aunt and uncle that the man who had raised him was not his biological father; both he and his older brother Eric were the children of another man. Rove has expressed great love and admiration for his adoptive father and for "how selfless" his love had been.<8> In 1981 Rove's mother committed suicide in Reno, Nevada.<8>
http://en.wikipedia.org/wiki/Karl_Rovegeorge bush's little sister died of leukemia when he was a child.
http://www.guardian.co.uk/politics/2003/sep/02/lifeandhealth.usaMichael Savage was born Michael Alan Weiner to a Jewish family with Russian origins living in the Bronx.<3><1> As a child, he worked. He described his childhood as difficult, due to his father's "gruff and profane" personality.<1> His father died of a heart attack in his fifties.
http://en.wikipedia.org/wiki/Michael_Savage_(commentator)
now that doesnt explain everyone, but the more rabid people with bios of deaths in their families when they were young, or abuse when youngsters.
and the pain comes out in many ways. as adults, if it hasnt been dealt with or acknowledged, it becomes anger and lashing out at everyone around them.
just my take on it.