While true that all countries had conflicts, most (maybe all?) of the developed world was never pillaged to the extent Africa and South America were. Not to mention a lot of the conflicts between those nations happened "voluntarily" between the fighting countries.

Africa especially, the current country borders were designed based on the division of property between all the European countries invading the natives' lands. That meant several tribes and groups were divided/grouped together, leading to wars that hold to this day. If I'm not mistaken the Rwanda Massacre is the major example of that coming to fruit