Despite frequent complaints about "Christo-fascists," much of this stems from the Protestant Reformation. Protestantism sought to wrest control over spirituality from the bishops and cardinals and place it in the hands of the individual. Instead of pledging obedience the Holy Mother Church, one was encouraged to develop a personal relationship with Jesus through prayer and individual study of Scripture. In America, revivalism placed an emphasis on choosing to follow Jesus: God could wash away your sins and make you a new person in Christ, but only if you allowed Him into your life. (Of course, this called God's omnipotence into question - but taking a Calvinist approach, it was generally assumed that those who chose God were predestined to do so... ).
Compare this to the worldview of Homer or the anonymous author of Gautrek's Saga. Pre-Christian Northern and Southern Europe were united in a belief in inescapable fates. You could meet your destiny with bravery or cowardice, but you would meet it nonetheless. The Gods did not ask for man's consent, any more than kings asked for the consent of peasants. Compare it also to religious practices which arose in less democratic surroundings. Haitian Vodou has never had taboos against controlling love spells. Neither do they have the idea that the lwa must first get permission before entering your life: there are many stories of Houngans and Mambos who unsuccessfully tried to escape their date with the djevo by joining an Evangelical church. (Ten percent of your income is a less onerous burden than the cost of a kanzo and the continuing responsibilities of the priesthood).
The idea that one might have "free will" before Gods or governments is a very modern one. Certainly one has room to negotiate with the Gods: there are many stories of people putting off their obligations with a promise or an alternative service. But ultimately there are limits to our freedom: sooner or later, we may well run into the Divine "Because I Said So, That's Why." We will then have to face the limits of our power. We will have to realize that we are in the presence of Something Greater than ourselves, Something which existed before our ancestors were born and which will exist long after our descendants have returned to the dust. And, if we are fortunate, we will experience something of the holy awe and terror which mystics have always felt in the presence of the Ineffable: we will know the Divine not only in its love and its wisdom but also in its power.
(Coming up in pt. 2: the ethics of non-consensual spellwork).