When Joseph DiGiovanni described areas ravaged by superstorm Sandy on New York's Staten Island, he compared it to devastation he's seen before. "It looks like a war zone," he said. "We know what a war zone looks like, and it looks like a war zone." A U.S. Army specialist in Vietnam in the 1960s, DiGiovanni received two Purple Hearts for injuries he sustained when the ammunition belt of his machine gun was hit during an attack. He lost his left pinky finger and still has pieces of shrapnel in his chest and eyes. (It hasn't affected his eyesight "so far," he said.) Now, he's the commander of Staten Island's chapter of Disabled American Veterans, a charity founded in 1920 by veterans who…