Steve wrote this in the context of persons being punished proportional to their crimes (sins). As I understand the Universalist position, there is no punishment for the purpose of retribution in their system. All punishment is solely for the purpose of "correction".
Ultimately, it is for the purpose of restoration.
If this is so, what certainty is there that the moral atheist or agnostic will not be more recalcitrant than a Hitler or Stalin?
I would say there is no certainty. Perhaps the difference between Hitler and a great many other people is that Hitler was in a position that enabled him to act upon what was in his heart. How many other potential despots have there been who, fortunately, never amassed any power outside of their own household? Maybe some are even those who present themselves, not as atheists or agnostics, but as Christians.
What scriptural proof is there that there is a correlation between the degree (or amount or number) of sin committed in this life and the amount of "correction" required to bring about repentance in the next?
I don't agree with the premise. I don't believe that "sin" is purely a matter of action (or even intent). I believe that we are so immersed in sin and so mixed in our motives that even when we try to do good it is still tainted. Calvin called this "total depravity". Not that we are totally depraved, but that there is nothing in us that is free from some element of depravity.
And once they are "corrected" and repent, are they punished any longer, since thay are "saved just like us"?
I don't see it so much as a juridical or transactional scenario, where X amount of punishment is prescribed based on X amount of sin. Rather, I see it as a relational scenario, where one is faced with who God and Christ really are (is?) and, in the light of that, one is faced with one's own miserable condition. The sin, and it's effects, are "burned" away, because they cannot remain in the presence of God. For some, there may be little left.
One of my favorite quotes from C.S. Lewis comes to mind:
"People often think of Christian morality as a kind of bargain in which God says, 'If you keep a lot of rules, I'll reward you, and if you don't I'll do the other thing.' I do not think that is the best way of looking at it. I would much rather say that every time you make a choice you are turning the central part of you, the part of you that chooses, into something a little different from what it was before. And taking your life as a whole, with all your innumerable choices, all your life long you are slowly turning this central thing into a Heavenly creature or into a hellish creature: either into a creature that is in harmony with God, and with other creatures, and with itself, or else into one that is in a state of war and hatred with God, and with its fellow creatures, and with itself. To be the one kind of creature is Heaven: that is, it is joy, and peace, and knowledge, and power. To be the other means madness, horror, idiocy, rage, impotence, and eternal loneliness. Each of us at each moment is progressing to the one state or the other."
Where I differ from Lewis is in the belief that even at its hellish worst, the human soul is not beyond God's ability to save it, though the more twisted by sin, the more extreme that process might be. Lewis famously said "The doors of Hell are locked from the inside." I find in that statement a gross underestimation of God's omnipotence and omnipresence and relentless love.
Quite often in this life the one who has sinned greatly is more readily converted than the moral unbeliever.
So very true.
It will not do to cite texts where God chastens His children in this life; they are inapplicable to the case. We are talking about His enemies.
Yes, His enemies. "And such were some of you." What is God's attitude towards His enemies, as displayed in Jesus? "But I say to you who hear, love your enemies, do good to those who hate you..."; "Father forgive them, for they don't know what they're doing."; "For if while we were enemies we were reconciled to God through the death of His Son, much more, having been reconciled, we shall be saved by His life."; "For it was the Father's good pleasure for all the fullness to dwell in Him, and through Him to reconcile all things to Himself, having made peace through the blood of His cross; through Him, I say, whether things on earth or things in heaven."
I am asking for a response from any of the CUs; Steve does not claim to be able to answer for you.
Though I commend him for doing a very good job so far, because he seems to strive for fairness and accuracy. Although he is not a Universalist, I would feel comfortable having Steve explain what Christian Universalists believe. I cannot say the same about Rick, Bob or yourself.