In fact, the first link points out a clarification that is wholly satisfactory (i.e. don't execute unless it is truly a last resort to prevent more deaths):
"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 are 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 non-existent."
Again, thank you. As a result of the clarification I no longer I am at odds with the Catechism.
Some Catholics are far too eager to exercise the death penalty and would use it in a manner which is not restrained by the cautions above.