Basic Trope: "Uncivilized" peoples are shown as being morally superior to "civilized" people.
Straight: Bob comes from a modern society filled with dishonest, corrupt, greedy politicians and businessmen. He comes into contact with a tribe of "savages" only to find out that they are more diligent, honest, and in tune with the earth than his own society is.
Enforced: "The plot requires Bob to encounter a nomadic tribe, but we can't portray them as savages. Not in this day and age. Let's have Bob view them as a welcome change from the corrupt city people he's always known."
Lampshaded: "Don't worry, they may be stupid, but they are nice."
Invoked: The savages don't believe in war or violence.
Defied: "Screw nobility! I'm going to act like a REAL savage!"
Deconstructed: The work examines poverty and hardship caused by a life of hunting-gathering or subsistence farming. A life of near constant desperation makes it hard for the tribe to create the moral codes we'd expect from Noble Savages. Truth in Television as nomadic tribes had little room for compassion to the sick and disabled. Infanticide was also common.
Reconstructed: But in spite, or maybe because of, all this hardship, the moral code and honor they adopt are iron clad and makes them more noble than those who are not "savages"