People living next to other people they like to live next to is called freedom. Throughout the history of the United States, immigrants have had some tendency to settle near other immigrants who speak the same language or who have other commonalities. (My maternal grandmother's parents apparently came over from newly reunified Germany as part of a "colony" of a large part of one Bavarian town who moved to Colorado together. She was born in the United States, but her entire formal school was conducted in the German language.) But people in the United States live in one place or another for many reasons of convenience that tend to mix together people of different ethnic backgrounds. It is an unusual American who doesn't have ancestors from more than one country of origin, and each new local cluster of immigrants finds plenty of sons and daughters forming families with people who don't share the same ethnic heritage.

Moreover, the worry about monoethnic communities isn't really responsive to the fine submitted article, in which the proposal was to have immigration from multiple countries (three were named) dotted among all the places where there are houses in default.

Umm, America has been through that process ever since colonization. German and Irish Boroughs in NY, Cubans in Miami, Chinese in SanFran, Mexicans in the Southwest.

America will be fine, we're an immigrant nation. Sure, a large influx is a terrible idea, but to shut off immigrants is protectionism and hurts in the long run.