This excellent video by Pat Condell brings up a lot of interesting points about multiculturalism and Islam.
I think liberals are missing a trick with this whole multiculturalism thing. The right seems to want to throw out the baby of general cultural and racial tolerance with the bathwater of Islamic barbarity, but the many on the left seem intent on protecting the bathwater.
I'm in favor of neither course. I think multiculturalism—in some sense—is critically, fundamentally important to a democracy: There is no set of arbitrary cultural values that is objectively privileged. On the other hand, we in the West have spent the better part of the last five centuries developing not only a culture, but also a set of legal and ethical traditions. It is those legal and ethical traditions which deserve our protection, not our "culture".
Where each person comes from—language, history, traditions, manners of dress, holidays—are both nontrivial and important. We are richer for celebrating them. I'm glad we celebrate Cinco de Mayo, I would be equally glad to see a celebration of Eid. I'm one of the few (I think) atheists who likes Christmas, at least in an abstract sense (after raising two children, I'm kind of burnt out on the holiday). I have no objection to seeing saris, and I object to the hijab only because it is a mark of misogyny and the oppression of women.
Cultural and racial diversity is not only unobjectionable, it's necessary. But along with cultural and racial diversity, in one nation we have to have one law and one system of public ethics. All of this cultural diversity has standing to contribute to this one law, but one law we must have. And the existing members of a nation have an interest in protecting their law and public ethics and acculturating newcomers and immigrants. The whole world does not get to actually vote on American, French or British law, or even Iranian or Saudi law.
Criticism becomes racism and bigotry only when it criticizes that which does not affect ethics and law. It doesn't matter to the law if you wear a sari; it doesn't matter to public ethics if you're brown, it doesn't even matter directly to law and ethics if you stick your ass up in the air five times a day and proclaim your submission to Allah; it matters no more than sitting in a church on Sunday. It does matter, at least here in the West, when you beat your wife, murder your daughters, mis-educate your children, and in general fail to integrate yourself into the social, legal, political and ethical system of the country in which you live.