Oppenheimer opens with a minute of silence, and then the chatter begins. No wonder Oppenheimer, called in for congratulations by President Truman after Japan’s surrender, says: “I have blood on my hands.” Oppenheimer is a restless, incessantly mobile film. I admire the film’s resolve to be about something more than the bomb, tying Oppenheimer’s increasing political troubles to McCarthyism, Cold …