True - and I believe this because this is what the Church has always taught. Are you saying you don’t accept this teaching?
*Legitimate public authority has the right and duty to inflict penalties commensurate with the gravity of the crime. *CCC 2266
The State has responsibilities that are different from those of the individual. As you can see from above, the State has not just the right to punish but it has the positive obligation to do so. The individual is forbidden to do so. This is a question of justice - a fundamental matter of right and wrong - which the State has the duty to maintain.
For the fundamental demand of justice, whose role in morality is to maintain the existing equilibrium, when it is just, and to restore the balance when upset. It demands that by punishment the person responsible be forcibly brought to order; and the fulfillment of this demand proclaims the absolute supremacy of good over evil; right triumphs sovereignly over wrong. (Pius XII)
Ender