Torture is what logically follows when separated from God. Hell is devoid of anything related to God because God is not present even remotely. Comfort, happiness, joy, pleasure, companionship -- these are gifts from God. While these things are abused on earth (selfish-pleasure for example), these are things that God has given to us...we don't always experience them here on earth -- sometimes, we may experience worse -- but we do experience them in heaven.
They can't be experienced in hell because God isn't there. Torture is the only other alternative because it is a removal of those things. It's loneliness, pain, sadness, constant distress.
God is a God of love, justice, but even logic. It would be illogical to have a place devoid of God and still find a gift that only God gives us.