Jabba the Hutt asks for a passionate kiss. You really don't want to do it and you don't. So he asks you again the next day. And again the day after. And so on. Each time Jabba asks you, there is some small chance you'll agree. Let's say that that chance is always at least one in a googolplex. Now suppose you and Jabba live forever. He asks you every day. Then by the Law of Large Numbers, it is nearly certain (i.e., has probability one or one minus an infinitesimal) that one day you will agree, no matter how disgusted you are by him.
The practical inevitability of the kiss means there is a sense in which your agreeing has been forced out of you by Jabba's eternal nagging, even though you were free on the particular occasion when you agreed to the kiss. We might say that you were quite free not to kiss on day n, where n is the day you actually kissed Jabba, but you were not really free never to kiss him. Yuck! How is it freedom when you are guaranteed to kiss a disgusting giant slug?
Now the two best alternatives to the traditional Christian doctrine that those who after a set deadline (death, say) opt against God are excluded from heavenly union with God are:
- Imposition: God imposes moral transformation on those who do not freely opt to love him.
- Endless Second Chances: God ensures that those who refuse him nonetheless always have another chance.
It's pretty plausible (pace compatibilists) that in Imposition, God takes away the agent's freedom to refuse him. But if the eternal nagging argument works, then in Endless Chances it looks like God all but takes away the agent's freedom, making it all but inevitable that the agent will eventually agree.
It is offensive to compare God to Jabba the Hutt. Yet for the person who is opposed to God, eternal union with God is subjectively rather like kissing Jabba the Hutt. Nor would it make the story more palatable if Jabba were to promise to make you enjoy the kiss, say by exuding pheromones or changing your preferences, as soon as you say "yes" to him. Of course, objectively God is infinitely lovable--but those have rejected him have set their hearts against that truth.
Objection: God could set up a version of Endless Second Chances on which it is not inevitable that the agent will agree by allowing each of the agent's refusals to affect the agent's character by even further lowering the chance of subsequent acceptance of God's offer. If the subsequent chances decrease sufficiently (say, by a half each time), the overall probability of eventually accepting might be significantly different from one.
Response: Yes, but this loses out on what I take to be one of the main merits of hell, that hell stops the agent's moral deterioration. On this picture, there is a significantly non-zero chance that the agent will continue morally deteriorating for eternity. And that's unfitting.