The four die-hard Redskins fans thought the opportunity was as golden as the vintage helmets of their favorite football team: “The Daily Show with Jon Stewart” wanted them to appear on the Comedy Central program to defend the team’s name, which has been under relentless attack. The Redskins Nation citizens eagerly signed up, most of them knowing that they might be mocked in their interview with correspondent Jason Jones. But several hours into the Sept. 13 taping of the yet-to-air episode, the fans, all from Virginia, said they were suddenly confronted by a larger group of Native American activists —...