It used to be that people in prison were there for actually doing something bad. Whether they were guilty or not is a different issue, but they had been convicted of committing some act of force or fraud against an innocent, individual, victim. Not so anymore. Now while there are still bad people in prison, the average prisoner is strictly a political prisoner, convicted of violating some nonsense "law" and "victimizing" the government which falsely poses as "society".
Things that should be treated as a medical or emotional problems, like severe addictions, are punished in harsh ways, causing innocent lives to be destroyed. Not submitting to the government's theft schemes is a big no-no today. Caesar must be given tribute. Things like peaceful gun ownership are punished with draconian penalties that would have been ridiculously unthinkable a generation ago, even though the "law enforcement culture" was not that good even then.
There is also the problem of the average juror not knowing their responsibility to judge the law as well as the facts of the case. In this way, many people who deserve no punishment are railroaded into prison by corrupt judges who work for the government; the very government which is the problem. What do they say about letting the fox guard the henhouse?
We all need to stop automatically thinking of people in prison as criminals. Now that the criminals run the "justice system", the distinction is rather dicey.