Zizek is almost too kind to multiculturalism,Diversity, etc. The coining of these terms marks the gravestone on the Black Liberation Movement of the '60s. That movement having been stopped (mostly by murder, e.g., of Hampton) and other repressive measures, partly by granting of minimally necessary demands an the consequent creation of a black "middle class" with interests of their own independent of Black Liberation, a polite replacement was needed to sop up or isolate any remaining serious struggle against racism. Multicultralism did the trick.
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In Zizek's debate with Bernard Henri Levy late last year, he makes almost precisely this point in almost precisely this way.
About which, see:
<http://mailman.lbo-talk.org/pipermail/lbo-talk/Week-of-Mon-20090105/000219.html>
.d.