In the US, there are areas afflicted by various levels of gang activity. Many gang members have grown up in these same areas. Many crimes in these areas go unreported or otherwise unsolved. (Think Brownsville / East New York or something.)
The theory underpinning most of these wishes, insofar as these wishes exist and they have a theoretical rather than emotional underpinning, is that there exist a class of offenders who guilty of crimes far in excess of what they have been convicted for, that they have internalized norms condoning things such as violence and theft, and that if released they would continue to pose an ongoing risk to society.
Assuming their original imprisonment to have been the just consequences of one act for which they have been convicted, then the subsequent fantasy imprisonment would be the just consequences of the other acts of which they are (or are forecast to be) equally guilty but for which they have not been convicted.
N.b. The appropriateness and efficacy of these wishes, specific materializations of these wishes, and the way that they interact with other concerns involving the rule of law, the fundamental dignity and rights of Man, and the greater good of society... all of that is not addressed in this post, because the nature of crime and attitudes towards crime in America is a complicated topic and this post is short.