A problem facing process-egalitarianism: Why do individuals surrender autonomy to political community?

This comment accepts the distinction that Duncan Stibbard-Hawkes and Chris von Rueden make: the difference between process-egalitarianism and outcome-egalitarianism. It also accepts that most historical societies care more about process- than outcome-egalitarianism. However, a question remains. If people care about process-egalitarianism, how come they are ready to surrender autonomy - i.e., ability to make decisions of their own - to a political community?