FORT MORGAN, Colo.—For years, workers at the Cargill beef plant in Fort Morgan, Colorado, have been forced to choose between their jobs and their basic human dignity. Denied permission to use the bathroom during shifts, some soiled themselves on the production floor rather than risk discipline. Now, 1,700 members of Teamsters Local 455 are locked out of that same plant because they dared to reject a bad contract offered by management that would …