I think that multiculturalism is the amalgam of the following:
1) Dogmatic ideas that "ethnic nation-states are stupid" and that they should thus be changed - expressed in this thread e.g. by
Bill3000 here.
2) Refusal to admit that mixing of different nations and ethnicities via immigration is highly likely to cause friction and problems as a result; or stating that benefits of such mixing will
a priori outweigh such problems; or blaming all such problems on the host country, who "simply hasn't been accepting and tolerant enough"; or merely dismissing such problems by saying that they are all "solvable over time". The last one is potentially true, but still does not answer the question why should we want to be saddled with solving them in the first place. These positions have, with varying degrees of reasonableness, been put forth by numerous people in this thread, including
you. I won't deny that there are countries which have, over the course of their history, greatly benefitted from immigration - I am merely stating that this result is far from granted, nor even solely in the hands of the host.
3) Naive belief that all cultures are always compatible enough to happily exist side-by-side while "being treated equally under the law and following it" - expressed in this thread by e.g.
Mise here. This viewpoint ignores the fact that laws themselves are very much a product of culture, not some universal supracultural phenomenon. Who gets to write these laws then?
Japanese and Arizonans, for example, could hardly be subjected to same gun-control laws without one side feeling extreme discomfort. The best they could hope for would be some sort of a lose-lose compromise. And to improve my earlier reply to
Formaldehyde: I would likely find a township of Christian Fundamentalist gun nuts as potentially unsettling neighbors as a village of Pashtun tribesmen I referred to earlier in this thread. I wouldn't be troubled for having to share an office cubicle or bus with one, but I would be quite worried about them gaining any local or national leverage.
And what do I want?
Basically the opposite:
1) Respect to wishes of people who prefer to continue living in a nation-state - don't attempt to engineer these into different kind of states. There are plenty of those in the world as well and I certainly ain't going to force them down my road either. That does not mean that already present minorities should be expelled, of course.
2) Understanding that creating a culture mix via immigration can cause problems; that the benefits are to be discussed and weighed against the costs; that every conflict has at least two sides and that it is safer to err to the side of caution when in doubt as such conflicts are far easier to create than to quench.
3) Recognition that the law of the host country must be respected as is and when it conflicts with one's beliefs or traditions, then those beliefs and traditions need to change rather than the law.
If everyone in a society is happily adhering to the same laws, then that society is, in fact, not multicultural, irrespective of how many skin tones or cuisines it contains.