American democratic lifestyle is based on majority rule, and multiculturalism is a great way to organize the minorities as separate from the mainstream. Once you have the group in a box, you can apply themes to its culture. This is painfully blatant in the arena of globalization, where African culture can be described as anti-democratic, Arab culture as violent, and Chinese culture as docile and obedient. It is even used in reverse to describe American culture as superficial. The systems of advantage in our society and in the world have much to benefit from forcing people to stay in their box, and even more by calling it human nature.
Multiculturalism is a cover-up for a new racism.
That is where it all collapses back to biology, more strongly then ever before. For if we are born with a capacity to be acculturated, there is no way to deny it. Unlike ideas of racial difference, no amount of genetic research can topple the idea of the cultural human. Science has been bypassed, and scientific facts can no longer help us in fighting the new racism. We must fight it on a different level.