Diversity is a strength?

can someone explain to me how diversity is a "strength"? what exactly is the benefit of mixing people of random languages, religions, ancestries, eye colors, hair colors, height, weight, intelligence, sexual orientations, disabilities, and classes in a small localized area and forcing them to reproduce with one another? because this has never resulted in a single discovery or invention. only poverty, criminality, disease, and civil strife.

differences in people are the number one cause of war. stop the hate. separate. give every group their own land.

>>27
Black children sit, crawl, walk, and put on their clothes earlier than Whites or East Asians.
During prolonged winters there was evolutionary selection for higher IQ created by problems of raising children, gathering and storing food, gaining shelter, and making clothes.
I think the main evolutionary bottleneck is that winter requires planning, so all individuals incapable of planning were automatically out.