Why is America's Housing so Segregated?, Simon Glenn-Gregg, The Century Foundation, May 5, 2016, available here

There is a great myth of a “natural neighborhood” that has been pervasive in the orthodoxy of public planning discourse in the past century. This supposedly well-intentioned approach to city planning originated in the concept of “ideal” neighborhoods as consisting of 5,000 to 10,000 people, and is largely based on the mid-century concept of suburban towns: isolated collections of people in a cohesive, non-diverse network with an innate social network. The insidious aspect of this myth is in using it to justify the creation of residential class and racial divisions, in attempting to forge homogeneous “natural neighborhoods” in the midsts of pluralistic cities. Throughout the past century, hordes of public and private interests came together to use this myth to engineer class and race segregation.