Many of my reviews are facetious, but “Man On Fire” (2004) is too good to deserve that. It’s also too dark for some people to like or understand. I think that says more about those people than about the movie itself. It’s beautiful and ugly, jarring and tender, bloody and ethereal. Denzel Washington, an alcoholic former (CIA?) assassin, turns up in Mexico. His paramilitary buddy, Christopher Walken, helps him get a job as a little girl’s bodyguard, setting off a story of vengeance, amorality, justice and classic movie lines. Forgiveness? That’s God’s job. Denzel’s just there to arrange the meeting.