This is an interesting passage in the letter:
The perfection of baptismal grace found in the Sacrament of Confirmation is not dependent upon age or knowledge of the confirmand. The grace that is conferred is a free gift and "does not need ‘ratification’ to become effective" (CCC, no. 1308). The common practice of high school or middle-school reception of Confirmation could give the impression that somehow the sacrament is merited by virtue of age or training. In truth, the Sacrament of Confirmation is an effective vehicle of grace at any age as long as it is validly conferred. Thus those that receive the sacrament are able to reap its benefits from the moment of reception. The invisible benefits of this sacrament conferred at a young age could be of great benefit to young people as they grow toward adolescence and young adulthood.
I guess ... it's just that I'm struggling with my preconceptions :-).
The Baltimore Catechism says, "Confirmation is the sacrament through which the Holy Spirit comes to us in a special way and enables us to profess our faith as strong and perfect Christians and soldiers of Jesus Christ." It seems that, even with the sacramental grace conferred, a young child lacks the natural capacity to "profess our faith as a strong and perfect Christian."
And on a related question, doesn't giving Communion to young children assume that they're going to make a good Confession the *minute* they have the capacity to choose good and avoid evil? Obviously, if they have been baptized, they are free from sin until the age of accountability ... but there's a fuzzy zone there, isn't there?