In the Bichir brothers' sharp-edged 'eXtras,' a call for more humanity in the immigration debate

“I need the Mexicans looking dispossessed,” a frustrated assistant director barks at local townsfolk hired to add background color to the big-budget movie “Desposeidos!” In any dialect, the cue is all-too apropos: Their lowly status on the film set mirrors the societal bottom rung occupied by the...