Singer Zack De La Rocha, of the politically candid rap metal group Rage Against the Machine, has left the band, he announced in a statement yesterday. His brief explanation, according to Reuters, is that Rage’s “decision-making process has completely failed” and that the quartet’s “artistic and political ideal” had been compromised. In reply, his colleagues vowed to “keep it loud, keep it funky and most definitely rock on.” Rage, which champions such social causes as the rights of garment workers, performed at a protest rally outside the Democratic National Convention in Los Angeles last August. At the MTV Music Video Awards in New York last month, bassist Tom Commerford was arrested after he climbed aboard a stage prop and refused to come down, which made for some memorable TV moments, indeed.