Even if it's true that criminal gangs have, historically, often been organized by ethnicity (because the ethnic divisions are already there) it does not thereby follow that if you removed ethnic divisions, gangs would cease to exist.
In fact many American ethnic gangs were transplanted from criminal organizations that had already existed (and thrived) in a monoethnic environment.
@DavidSalo He's just dumb. Trying to sound intelligent on the subject but probably couldn't rub two brain cells together if you asked him about redlining and how that impacts his theories on cultural segregation.
@Fellixe All those oligarchs with pied-à-terres in Manhattan. Biggest concentration of international criminals outside of Monaco.