"Why would it be incomprehensible to believe He can cure the unrighteous?"
Not uncomprehensible at all. But according to your reasoning He does this after they have been in the fire for some period. If God is ultimately going to save all mankind is He going to somehow MAKE them love Him after the fire, why doesn't He do it before the fire?
Most people who are punished in this life don't come out of prison loving the people who put them there.
"God will reform those in the fire." Scripture? Did God reform the thousands of inhabitants of Sodom, Gomorrah and the cities of the plains when he saved Lot and his family?
God is not human, He is capable of restoring those He created, yes, even Sodom.
“For he must remain in heaven until the time for the final restoration of all things, as God promised long ago through his holy prophets.” Acts 3:21
of all things,
πάντων (pantōn)
Adjective - Genitive Neuter Plural
Strong's 3956: All, the whole, every kind of. Including all the forms of declension; apparently a primary word; all, any, every, the whole.
People reject God here and now for various reasons, A pastor may have sexually abused them, or someone in authority. We don’t know all the reasons, many by no fault of their own reject God because of a poor reflection they may have learned from those in authority over them. Or they may have been raised in a culture of another religion that enforced incorrect information on the true living God. In any such case, God who is full of mercy will reveal Himself at death or after, and like Paul they will experience the true living God who will heal them of their ignorance or lack of knowledge.
True story, back in my days as a Southern Baptist I crossed paths with a atheist women who was set against Christianity. She mocked God on a daily basis and my desire was to set her straight, and provide her scriptures. We would go back and forth. One day as I was praying without a doubt God instructed me to stop pushing scripture on her, I was confused and asked why? The answer I received from God was that I was pushing her farther away from Him. This of course was not my intention, He then instructed me
To just love her where she was at, and then I also became aware that she was molested by her father who was a Pastor. We like to think of things as black and white thinking it is so clear who God will redeem, when it comes to situations like this women. It became clear to me that God loved this women, and knew her painful past and her judgment would include this horrific trauma she experienced. This type of judgment is also part of our justice system. When A human judge is sentencing a criminal the judge will take into consideration what wrong have may have shaped the criminal. It is called virtue of mercy.