Kenan Malik critiques it:
There are two ways over the past half-century in which we've stopped treating people as citizens. One is through racism. The racist says "you're not a citizen, you don't have full rights in this society because you have a different skin colour, you are foreign", etc. The second is multiculturalism. The multiculturalist says: "we treat you not as an individual citizen, but as a Muslim or a Hindu or a Sikh or a black". The irony is that multiculturalism developed as an attempt to combat the problems created by racism. But it has recreated many of the problems by treating people not as citizens but as members of groups, and by formulating public policy in relation to those groups and not in relation to the needs of individual citizens.
(Hat tip: 3QD)