I think it is a fair point to say that national authorities are better situation to determine the necessity of capital punishment than the Pope. For example, a developing nation with fewer resources might not be as capable of indefinitely detaining a violent criminal, and in this case it would be problematic for them to put at risk their own citizens in order to avoid the death penalty.
However, the Pope likely also considered this, and felt comfortable revising the catechism in any case. Clearly he believes that every nation of today, no matter their wealth or resources, has at the very least the ability to avoid the death penalty.
Admitting that there is any scenario at all where capital punishment is permissible does not necessarily mean that anyone is elevating themselves over against the Pope. In the words of the catechism, “Recourse to the death penalty on the part of legitimate authority, following a fair trial, was long considered an appropriate response to the gravity of certain crimes and an acceptable, albeit extreme, means of safeguarding the common good.” Here it is admitted that the death penalty was “long considered” to be acceptable. If it was evil intrinsically, then it could never have been acceptable.
I think the people that have misread the catechism know who they are, I don’t want to name them.