As a critic, I should probably take offense at the title of “ The Last Critic .” The movie is a captivating portrait of Robert Christgau , the legendary music writer who was one of the founding fathers of what was once known as “rock criticism.” (These were the days before poptimism, not to mention the Taylor Swift fan base.) To be fair, the film never asserts the claim of its title — that Christgau was or is “the last critic.” He was, in fact, one of the first writers to establish rock