The Elementals are a pretty fickle bunch, but they've created a fairly good system for controlling people.

They whacked the planet when Black Magic and White Magic drained the lands of Aether. They finally allow people to live in the Twelveswood again, but with conditions. They established a privileged caste (Padjal) and give them unique and great power (White Magic, one of the things they flooded the world in the first place for). The Conjurers are then granted power from the elements in return for further service, creating a borderline religious institution, and making the rare few Hearers about as important in Gridania as Inquisitors are in Ishgard. From there a strict, unyielding national propaganda is created and enforced to foster mistrust of the outside world, cutting the Gridanians off from viewpoints the elementals don't like, further controlling the population.

At the end of the day the Elements had created their own little meat army of puppets who'd throw themselves on swords if the Elementals told them to do so through a hearer or a padjal. Lo and behold, the Calamity wrecks the Twelveswood and the elements are weakened, and now they reply on their army of meat puppets. When that proves to be not enough, adventurers are given the Okay, mostly because they don't stay in one place too long, and so won't overtly affect the generations of social and psychological conditioning.

Honestly, the elements are like cultists. It's a bit disturbing when you think about it.