Unfortunately, it's how humans work. As a species, we did not progress beyond the Middle Ages. Our tech did, but we didn't. Still the same tribalism as before.

Unfortunately, it's how humans work. As a species, we did not progress beyond the Middle Ages. Our tech did, but we didn't. Still the same tribalism as before. When we plunder the other village, take their crop and their wives, it's to bring justice to the world. When they come to us, take our crop and our wives, they are evil aggressors. Nothing has changed, and probably will not change anytime soon. Thousands of years of evolution are still stronger than whatever thin layer of civilization we try to put on top.