This is another anti-American cave-in to multiculturalism. I challenge anyone to name anywhere in the world throughout man's history that benefited from multiculturalism.
It depends on how it is used. In the current sense, probably not. But if a group of immigrants came together in a community and worked together for a common purpose (becoming adapted and part of the society), while respecting differences, that is not bad. Our language, many of our customs, culture, etc. often reflect the many different cultures that have become a part of American society. That isn't bad. It's when they choose to withdraw themselves in their own little places that it is not.