Admit it: For years you’ve been burning to know what ol’ Phyllis Diller really thinks about electric cars, which first (dis)appeared in her youth. “They were very quiet,” she recalls. (Isn’t a Mack truck quiet compared to Phyllis Diller?) The real question is why this purportedly impassioned documentary investigation of a great subject—the culture’s conspiratorial dismissal of eco-friendly alternatives to the gas-guzzler—would assume such massive viewer disinterest that it coats the pill with C-list celebrity NutraSweet, including Martin Sheen voiceovers (“As the 20th century gathered speed . . . “) that would sound unforgivably hackneyed even on basic cable. An opening vignette in a California cemetery has GM’s produced-and-abandoned EV-1 being “buried” by tearful mourners (ha-ha); subsequent title cards, complete with Fox News–ish animation (whoosh!), finger so many of the usual suspects (e.g., carmakers, lawmakers, big oil, us) that the titular question might as well be Who Didn’t Kill . . . ? Director Chris Paine’s choice of talking heads leads you to think that famous people were the only ones lucky enough to have leased GM’s now flattened roadster—until the awkward slip of his would-be audience surrogate, a “former EV-1 specialist,” appears to reveal that his own model has somehow been tucked away for safe keeping. Another few of these squandered opportunities for art-house muckraking and we’ll need someone to ask who killed the left-wing documentary.