"The crazy thing about multiculturalism, or "diversity", is that there's no bright side. Said another way, a fully multiculti society, one which "celebrates diversity" has never existed and never can exist. "Like all such fantasies, attempts to create one can only be accomplished by
an all-powerful state willing to kill to overcome the human nature which stands in its way."
I think you just gave a close description of the American Civil War.
I don't think that the Army of the Potomac had any intention whatsoever of implementing multiculturalism or diversity.
In fact, the people who brought boatload after boatload of Africans to live and reproduce here created the first multicultural society in North America - and they were terrified by it.