When Richard Demsick learned of the killing of Ahmaud Arbery, he immediately thought about the privilege he had as a white man. Arbery, a 25-year-old black man, was shot dead while jogging in February after being chased by two men — Gregory and Travis McMichael — who said he looked like a break-in suspect. In a video that trended after Arbery's death, the McMichaels could be seen pursuing Arbery in their truck while Arbery ran. Travis McMichael left the truck holding a gun and, after a brief struggle, Arbery was dead. The McMichaels later told the police they believed Arbery...