There is a reasonable body of evidence among our closest genetic relatives, Chimpanzees, to suggest that murder and mob violence might be not that foreign to the makeup. I think it's difficult to understand these impulses when you are so far removed from the pressures of the hand-to-mouth world of subsistence foraging, but if you were sudently subjected to a great deal more survival pressure, I would suggest that most people's behaviors would alter. I saw a show on some National Geographic Chanel that suggested that as the body progressively undergoes starvation it shuts down metabolism in unimportant areas. The last three are the brain, the respratory system and the heart, and when it has to go from there, the body lowers metabolism in the higher brain functions that inhibit canabalism. At that point, you'd essentially be operating with the moral guideposts of a person who'd had a lobotomy. The Bosnian racial tensions are several thousand years old, btw. As with the other cases of colonialism, Soviet attempts to create a Yugoslavia where none existed through external pressure only sublimated the tensions until the pressure was released.
Yugoslavia pre-existed the Soviets and also broke with the USSR in the 1950's. Yugoslavia also was economically and socially far far more successful than other socialists countries. So while yes the ethnic hatreds in Yugoslavia date back centuries this wasn't some economic basketcase being held together by a totalitarian iron fist. What happened in Yugoslavia was almost akin to if Scotland and Wales decided to violently succeed from the modern UK.
