Go to Italy and you can visit Pompei & Herculaneum. Both cities destroyed in 79AD. They had a thriving community with a parliament, zoning, commerce, solid housing structures, sewers, roads, etc. It's all there for you to see firsthand.
Then 1,400 years later Europeans visit America. They find people clothed in animal skins living in portable housing. I'm sure the native Americans of 79AD were very similar to the NAs of 1500AD. So why didn't they progress at close to the same rate as did the Europeans?
Europeans settling in what is now North America is the original attempt at diversity. Since diversity is our strength, the arrival of Europeans to the new world should be celebrated robustly.