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

[FlatAssembler]

prison isn't supposed to be a creator -or- a solution of/to psychological problems

Punishment means causing psychological problems to somebody, does not it?

we were looking for people who..by their imprisonment, would lead to more or less dead or injured -other- people.

To be honest, I did not understand everything you wrote. I assume you mean that prisons are a good thing in that they remove violent criminals from the society. But the fact is that recidivism for violent crimes is very low. Of 100 murderers, only about 1 or 2 of them murder again. And, again, even if recidivism of violent crimes were a problem, putting murderers into prisons from which they will return with even more psychological problems is hardly a solution.

assuming they had any at all, which I doubt.

Why would somebody who does not have psychological problems murder somebody?

And say what you'd do in the interim with the criminal dregs that need locking up for public safety and peace of mind.

My friend, recidivism of violent crimes is very low. So low that it is almost not a problem. Out of 100 murderers, only 1 or 2 of them will murder again. And even if recidivism for violent crimes were a problem, how exactly would putting them into places from which they will return with even more psychological problems make the society safer? If anything, it should make the society less safe.