The fact that they were able to expand so much as colonists in Planet Norma was not because they were particularly intelligent or gifted, but rather because they hit the largest possible jackpot.
Resurrection, even if it had a lot of limitations such as requiring resurrection towers and sacrificing 20 years of their lifespan, it still allowed those of them from Earth to hold a huge advantage over the natives.
The residents of Planet Norma were quite religious, so the mental impact was quite significant when they were facing an enemy that could constantly resurrect themselves.
Fighting hard to kill a foe only to have them come back unharmed after a few minutes was the stuff of nightmares—the kind that you did not know how to wake up from. Almost any army would slowly start to collapse.
