For two-thirds of its brief length, Scott Crary’s Kill Your Idols is content to competently survey the past three decades of downtown avant-rock, from Suicide and the No Wave explosion through Sonic Youth and the Swans all the way up to contemporary bands like the Yeah Yeah Yeahs and the Liars. But after about 45 minutes, the movie turns into something more like Kill Your Bastard Children, with No Wavers like Lydia Lunch opining vociferously against the current scene’s fashion-conscious posing and fundamentally derivative nature (“what a pandering bunch of postpunk pop mama’s boys”). While clearly not without merit, such complaints would be more interesting if we were allowed to know who exactly was being ripped; instead, Kill Your Idols pulls a few punches, tempering its respect for No Wave values like extremity and contentiousness with a more 2006 concern for not actually offending anyone in particular. The more sweeping “death of rock” pronouncements are rendered ridiculous by the inclusion among the interviewees of vital young artists like Eugene Hütz of Gypsy-punkers Gogol Bordello, but DNA’s Arto Lindsay gets at the essence of what’s changed over 25 years, noting sympathetically that “we didn’t have a whole industry selling us back to ourselves.”