Quick stab at Antisocial Surrealism:
Hip hop is critique through both symbolic transgression and exaggeration (often intimately related), increasing the power of the black underclass by becoming a highly visible stylish commodity. Weirding everyday objects -- dying sneakers, wearing gigantic chunky jewelry, etc. -- by taking consumerist logic to the extreme.
It's condemned for its lack of social realism -- not portraying the community in a way the Big Other (white middleclass america) finds acceptable, not depicting real situations in a journalistic way that calls for social amelioration, but exaggerating them for the pleasure they produce, perversely turning these weirded aspects of black underclass life into pleasures (they already were; consider rich whites slumming in jazz clubs in the 1920s for example) and amplifying this effect by an expert use of the commodity form. Instead of begging for pity from the existing order, this tactic destabilizes the entire system which must revolutionize its means of production in order to keep up co-optation. And thus hiphop becomes one of the languages par excellence of late capitalism.
This draws criticism from many corners -- civil rights generation sees it as a rejection of their calls for justice (which it is), nationalists and leftists see it as selling out to capital (which is not wholly the case, though HH has always been complicit with commodity capitalism), and also from reactionaries (for whom the black body represents a kind of primitive authenticity) who can't fathom that rappers might be ironic, exaggerated, sarcastic, playful, etc. but must always represent ESSENTIAL TRUTH.