To maintain a soul in everlasting agony and torture is something that is incompatible with God’s benevolent nature. Purgatory would be fine. One commits some finite deed, which needs to be punished, and one spends some (unspecified but) finite time in purgatory, to “purge” the evil out of him. That would be a just sentencing. But infinite torture is different. It is rather strange that you see a the limited agony and the following eternal bliss as “unbalanced”, but refuse to accept that finite deeds cannot “merit” eternal punishment.
I think you are missing the point that God isn’t maintaining the soul in everlasting agony. The agony is due to a rejection by the soul of God’s love. Here’s a good analogy Eastern Catholics and Orthodox use to describe it:
Why We Need Hell By Frederica Matthewes-Green
First of all, hell is not a place. If you’re separated from your body and exist only as a spirit, you don’t take up any room. In the Hebrew Scriptures all the dead, righteous and unrighteous, abide in Sheol (the Greek Scriptures translated it “Hades”). It is a non-physical realm where the souls of all the departed await the Last Judgment.
But they don’t all experience it the same way. In Jesus’ parable of Lazarus and the Rich Man (Luke 16:19-31), the Rich Man is not sequestered in a bleak alternative dimension; he’s able to see Lazarus, and speak to Abraham. But he’s sure isn’t having a good time.
How can this be? Because the real answer to the “where” question is “in the presence of God.” Nothing exists outside God, making the concept of “separation from God” only a handy metaphor. “Whither shall I flee from thy presence? … If I make my bed in Sheol, thou art there” (Psalm 139:7-8). In this life, we perceive that presence pulsing through all material Creation. In the next life that materiality will be dissolved, and we’ll be irradiated by the living energy that sustains the universe.
Those who love God and prepare themselves to assimilate his light will begin to be transformed even in this life; they become “partakers of the divine nature” (2 Peter 1:4). But those who resist and ignore God “harden their hearts” (Hebrews 3:15). If they “love darkness rather than light” (John 3:19), they will find the inescapable brilliance to be searing misery and paradoxical blindness.
And that’s only a foretaste. What we experience as spirits can be termed “Hades” and “Paradise.” After the unimaginable resurrection and restoration of our bodies, true “Heaven” and “Hell” will commence.
How can the same Light affect people in different ways? Hearers of scripture in earlier generations would have seen this phenomenon every day. Before the age of electricity, light always meant fire. And fire requires respect. From earliest childhood they would learn that fire gives us warmth and light, but if mishandled, it deals agonizing pain, darkness and death. “Our God is a consuming fire” (Deut. 4:24, Hebrews 12:29).
“The same sun that melts wax hardens mud” is how Origen, the 3rd century Egyptian writer, put it. In the 4th century, St. Basil the Great used the story of the three young men in the fiery furnace (Daniel 3:1-30) as an illustration: the fire spared the prayerful trio, while the guards who threw them in were destroyed.
God’s presence is not just Light, and Life, but Love. And Love invites, but does not compel. The Prodigal Son’s older brother lived in his father’s loving abundance, but was bitter and resentful. To the pure, God’s purity shines clearly; but to the twisted, even His love appears untrustworthy and twisted (2 Samuel 22:27). St. Issac of Syria (7th century) wrote that those who suffer in the next life “are scourged by the scourge of love.”
This idea, that both heaven and hell are experiences of the same divine presence, is startlingly different from contemporary assumptions. But even more so is the next idea: hell is not a punishment. We assume God’s justice means settling the score; that each sin must have its payment, either in Christ’s blood or human writhing in hell. We can even sort of like the idea. Surely God will torture murderers and rapists and bad guys, and anyone who ever did us a wrong turn. Justice, we think, means finally getting even.
But as St. Isaac points out, God isn’t “just” in that calculating sense. “How can you call God just,” he says, when you consider the parable of the workers paid for a full day when they worked only an hour? Or the parable of the Prodigal Son, restored fully to his father on the basis of mere repentance? St Isaac concludes, “Do not call God just, for his justice is not evident in the things concerning you.”
God is not looking for repayment, but repentance. What heals a broken relationship is sincere love and contrition. What’s wrong with us isn’t a rap sheet of bad deeds, but a damaged heart, a soul-sickness, that plunges us into fearful self-protection, alienation from God and others. Paradoxically, this leads to death: “whoever would save his life will lose it” (Matthew 16:25).
This sickness elicits not God’s fury but his indomitable love, much like the urgent, grieving love a parent has for a wandering child. (Jesus’ parable was about the Prodigal Son, not the Indignant Accountant.) “It is not that God grows angry with us,” said the 3rd century Desert Father, St. Antony the Great, “but it is our own sins that prevent God from shining within us.”