How are we supposed to prevent wars without understanding what caused them in the first place?
But even then, modern popular commentary mislocates the causes.
There is a modern belief that multicultural societies somehow protect against ethnic and religious genocide. History doesn't show that to be true at all.
The Ottoman Empire was the longest and largest multi-religious, multi-ethnic, multicultural empire in history, but when it fell, it fell into genocide, population exchanges and ethnic and religious oppression, despite those populations living side by side for hundreds of years.
Again, look at the former Yugoslava. In some cities, many people didn't even know they were "croat" or "serb" because society had been so assimilated for so long. Didn't stop the killing though.
People constantly focus on nationalism and racism as though these are the primary causes of genocide. They aren't. In most cases, they are a symptom of the true cause, which is resource scarcity.
In practically every war, the fundamental core of conflict is access to resources: natural, infrastructural, industrial etc. The racism and nationalism evolves as a way to excuse why one group should have access to said resources over another.
You want to eradicate war and conflict? Eradicate pressurised resource scarcity by managing resources effectively and in a just manner.
Notice how very few governments and governing entities do this or even talk about it.