That's because the old and perfectly workable patriotic Melting Pot philosophy is the exact opposite of the leftist philosophy of Multiculturalism. The first resulted in newcomers turning their backs on their old loyalties -- while keeping aspects of their old culture and traditions -- in order to fit in and get ahead in life. Melting away the past to blend in and become a true U.S. citizen.
The the latter involves nurturing strident hatreds and aggressiveness in the name of remaining in all but citizenship (the name of some other country or ethnic identity).
The melting pot philosophy was by no means perfect, but the Multiculturalism philosophy is an ongoing and destructive nightmare. But then one does not expect anything less than that when something is rammed down the throat of this nation by the political Left.
