I know of no other part of the catechism that contains an opinion outside the competence of the Church. The Church has no special expertise about prison systems around the world.
Further, it is dishonest to quote only a portion of a single part of the catechism and ignore the preceding paragraph:
2266 The efforts of the state to curb the spread of behavior harmful to people’s rights and to the basic rules of civil society correspond to the requirement of safeguarding the common good. Legitimate public authority has the right and duty to inflict punishment proportionate to the gravity of the offense. Punishment has the primary aim of redressing the disorder introduced by the offense. When it is willingly accepted by the guilty party, it assumes the value of expiation. Punishment then, in addition to defending public order and protecting people’s safety, has a medicinal purpose: as far as possible, it must contribute to the correction of the guilty party.
2267 Assuming that the guilty party’s identity and responsibility have been fully determined, the traditional teaching of the Church does not exclude recourse to the death penalty, if this is the only possible way of effectively defending human lives against the unjust aggressor.
If, however, non-lethal means are sufficient to defend and protect people’s safety from the aggressor, authority will limit itself to such means, as these are more in keeping with the concrete conditions of the common good and more in conformity to the dignity of the human person.
Today, in fact, as a consequence of the possibilities which the state has for effectively preventing crime, by rendering one who has committed an offense incapable of doing harm - without definitely taking away from him the possibility of redeeming himself - the cases in which the execution of the offender is an absolute necessity “are very rare, if not practically nonexistent.”
It is perfectly acceptable to argue that California should abolish the death penalty. It is not permissible to claim that Catholic teaching requires it. Among those with this opinion are Popes Benedict XVI, Pius XII, and virtually all previous popes.
Many saints have been unjustly executed, including Joan of Arc, Maximilian Kolbe, Thomas More, and John Fisher. None of them argued that the state lacked the authority to impose the death penalty. More famously, most innocent, and possessing perfect knowledge on this issue, Jesus seems to argue the opposite:
"So Pilate said to him, “Do you not speak to me? Do you not know that I have power to release you and I have power to crucify you?”
Jesus answered (him), “You would have no power over me if it had not been given to you from above. For this reason the one who handed me over to you has the greater sin.”