That feels like a non sequitur argument, we should strive to reduce prison populations without worrying about absolutist. We could drastically reduce the prison population and list of crimes without hurting anything, first thing is stop prosecuting victimless crimes like pot smoking. Release the people convicted of non-violent drug crimes. Release the people who were convicted of stealing 25$ from the quickimart. Give people post prison treatment, get them a starter job. Don't just look to penalize them again.

Just like saying we can't reduce nuclear weapon counts in the us because russia and china are scary and we need them to stop them, we could still drastically reduce the count of them by about 100 without changing that.