Is Multiculturalism Wrong?

Is multiculturalism wrong? This is what the 3 most influential European leaders say now after they have tried it. We used to consider ourselves a "melting pot". But the left-wing PC crowed told us that we must not be a "melting pot" but rather multicultural. And once again the left-wing ideology is wrong and considered harmful to nations.
SARKOZY ON FRENCH TV
FEB 10, 2011
“We have been too concerned about the identity of the person who was arriving and not enough about the identity of the country that was receiving him.”
“My answer is clearly yes, it is a failure.”
DAVID CAMERON
FEB 5, 2011
“Under the doctrine of state multiculturalism, we’ve encouraged different cultures to live separate lives apart from each other and apart from the mainstream.. we failed to provide a vision of society to which they feel they want to belong. we’ve even tolerated these segregated communicating in ways that run completely counter to our values..
ANGELA MERKEL
OCT 16, 2010
“We are a country which at the beginning of the 1960s actually brought guest workers to Germany now they live with us and we lied to ourselves for a while saying that they won’t stay and that they will disappear one day that is not the reality this multicultural approach saying that we live side by side and that we are happy about each other–this approach has failed.  Utterly failed.”