This is very true. There is always a risk in releasing someone from prison who has been deemed rehabilitated. The people charged with making such determinations can and sometimes do make mistakes. But I do feel compelled to point out that in many countries where rehabilitation is prioritized over punishment, recidivism rates are actually much, much lower than they are in the United States. Norway is the most commonly cited example of this. They are incredibly merciful toward convicted criminals, yet their system is infinitely more effective than our own.