Well, technically sPeaking, gangs have wars over territory, resources and reputation just like everybody else did. They're actually more qualified to be on this show than Gladiators or Ninjas.
It should also be pointed out that THE DRAMATIZATIONS IN THE END AREN'T REPRESENTATIVE OF HOW THESE FIGHTS PLAY OUT IN THE SIMULATOR. They're just fun, susPenseful showcases of the weaponry used in the thousand battles. So you could susPend your disbelief at an Apache surviving two Cestus slams from a Gladiator.
And regarding that Match-up, yes, a Gladiator might have the advantage over an Apache in an Arena. An Apache, on the other hand, would be at home in the forest, prarie, desert, canyon, mountain, swamp and pretty much any other natural setting. So there's not much sense in saying the Gladiator was cheated. He was lucky this Apache didn't have a 6 shooter!