"Why is it reasonable to believe in prisons, but not in the hell?"

[FlatAssembler]

OK, how can one rationally believe prisons are a good thing? How can putting a criminal into a place from which he will return with even more psychological problems be a good thing? ... <snip>...</snip>

My bold.

I pointed out that sweeping statements wouldn't help you, and you come back with a sweeping statement. What would you have society do? Forget Karl Popper - he wasn't voted in to run any country or play any part in societal norms.

What is a "sweeping statement"? English is not my native language, my native language is Croatian.
As for what should a society do with criminals, my suggestion is to simply do nothing. Do nothing until there is a consensus among social scientists what they are about to do actually helps.
What difference does it make if Karl Popper was voted to run any country? He was a social scientist whose ideas are widely accepted today, to such a degree that social scientists get ridiculed for questioning them. Newton never controlled how the planets move, but his theories accurately predict that.