Disclaimer: I own nothing of Dragon Flyz, which is owned by Gaumont Pictures. Only the plot is mine.
The humans thought they knew oppression, but they didn't. Not when they were safe on their flying city, with the dragonators and the Dragon Flyz willing to defend them.
If anyone was truly oppressed, then it was the regular dramen.
They were routinely preyed upon by the dark dramen and the mutants, hunted down for slaves and for sport.
This had been going on for so long that there were entire tribes that no longer fought back, simply accepting their horrible fate after generations of being beaten down.
That was also what Dram was determined to change. Having had one success already, he made a point of returning to that village and teaching whoever wanted to learn how to fight back.
He taught them grappling, hand to hand, any kind of fighting move that would give them an edge against the next attack by either dark dramen, mutants or both.
He wouldn't let other villages suffer the same fate his own had, so long ago.