>>519691242
Ethnic diversity within 80 meters of a person reduces social trust. https://curis.ku.dk/ws/files/130251172/Dinesen_S_nderskov_Ethnic_Diversity_and_Social_Trust_Forthcoming_ASR.pdf
Ethnic diversity directly reduces strong communities. https://www.msu.edu/~zpneal/publications/neal-diversitysoc.pdf
Ethnically homogenous neighborhoods are beneficial for health. https://www.mailman.columbia.edu/public-health-now/news/living-ethnically-homogenous-area-boosts-health-minority-seniors
Diversity in American cities correlates with segregation. https://fivethirtyeight.com/features/the-most-diverse-cities-are-often-the-most-segregated/
Races are extended families. Ethnocentrism is genetically rational. https://www.amazon.com/The-Ethnic-Phenomenon-Pierre-Berghe/dp/0275927091
It is evolutionary rational to be friends with someone genetically similar to you. https://www.livescience.com/46791-friends-share-genes.html
Racism and nationalism are rational and evolutionary advantageous strategies. https://jasss.soc.surrey.ac.uk/16/3/7.html
Homogeneous polities have less crime, less civil war, and more altruism. https://www.theindependentaustralian.com.au/node/57
States with little diversity have more democracy, less corruption, and less inequality. https://www.theindependentaustralian.com.au/node/57
There is extensive evidence people prefer others who are genetically similar. https://psychology.uwo.ca/faculty/rushtonpdfs/n&n 2005-1.pdf