The more diversity a nation has the less likely voluntary associations are going to arise since people, in the context of diversity, tend to withdraw from Culture (see Robert Putnam’s “Bowling Alone.”) The more people refuse to build the voluntary associations that make for culture the more the State will centralize as it has no competition for authority from the social order matrix that is inclusive of the now reduced cultural infrastructure that once was built by voluntary associations that are no longer voluntarily associating (See Robert Nisbet’s “Twilight of Authority”). Hence it is in the interest of the Managerial State to foster as much diversity as it can.
Now combine this with the reality that diversity in religion, race, and culture ensures conflict between the competing religions, races, and cultures that are living cheek by jowl so that the only resolution of such conflict comes from the State and its enforcement apparatus and we see again the interest that the tyrant state as in embracing diversity.
Finally, the tyrant state also has an interest in continuing with the cheap labor that comes from the pursuit of ongoing diversity. Cheap labor favors the Mega-Corporation class and as the Mega-Corporation class is one and the same with the tyrant state (a revolving door existing as between them) the tyrant state pursues the interests of the tyrant Corporation class.