It appears many western sociologists and have gotten confused over the last half a century or so and have started building theories like castles in the air from dogma instead of rooting them in empiricism, not much different from religious theoreticians of a bygone era who insisted earth is the center of the universe.
The only reason for prisons and criminal justice of various to exist throughout history has been to (1) deter crime by threatening punishment and (2) give the rest of the society confidence that "crime doesn't pay" - because a system that has higher intrinsic trust and follows rules invariably outperforms ones that don't economically and often militarily. Yes part of such a successful system is graded treatment for people who have a better chance of rehabilitation as such folks are much more useful in society and tempering of justice contextually.
However trying to add additional tasks to the system, like rehabilitation or empowerment or economic development of a disadvantaged class serves only to compromise the core function and result in societal breakdown. These are all important tasks and they should be delivered through other parts of the government that are focused on these missions. It is perfectly fine for different arms of a government to have seemingly contradictory missions and these need not be aligned like how audit/controls and commercial functions are not necessarily aligned.