Narcissism of Small Differences
This is a concept first postulated by Sigmund Freud in 1917 and popularized by Christopher Hitchens in his National Post article.
The crux of the thesis states that communities and people who live close to one another are likely to engage in conflict over minor differences, rather than any large disagreements. In his 2010 article, Christopher Hitchens used the thesis as a framework to discuss ethno-national conflict, such as the conflict between Uzbeks and Kyrgyz in Kyrgyzstan.
The concept was talked about in episode 61 of the Making Sense podcast featuring Lawrence Wright.