This Balkanization is being carried out by communities who wanted to recreate mirror-images of their society back home. They do not want to mingle with others and even learn English. A melting pot presupposes assimilation and loyalty to the adopted country.
Yet, our legal immigration policies support such Balkanization thru entended chain migration and the sheer numbers that work against assimilation. We [the US] is accommodating ourselves to the immigrants [Hispanics] by making it easier for them to function in Spanish and not learn English, e.g. drivers tests, ballots, ESL courses, etc. We have never accommodated any other immigrant group to that extent.