If we all looked the same would their be less wars
Wars are usually about resources like land, access to ports, spices, gold, etc.., not race. When we start running out of drinkable water and crops start failing en masse due to global warming, there will be plenty of wars. TONS of them.
Meanwhile I'm not sure I would hold Brazil out as a model. Tons of crime and one of the greatest differentials between rich and poor in the developed word. Things are improving but skin color still correlates heavily with education and wealth, with whites and Asians way out front.