The OP’s question is a very good one. And I don’t understand the reasons myself, since the answer is so simple.
It has been in the past up to each Diocese Bishop to determine the teaching tools in his own Diocese. Teaching is each Bishop’s responsbility.
Look at the difficulties including heresis and schisms that have been taking place in the USA due to the lack of proper Catechesis.
However, here is what Pope Benedict said in his Motu Proprio of Oct 11, 2011.
QUOTE " 11. In order to arrive at a systematic knowledge of the content of the faith, all can find in the
Catechism of the Catholic Church a precious and indispensable tool.
It is one of the most important fruits of the Second Vatican Council.
In the Apostolic Constitution Fidei Depositum, signed, not by accident, on the thirtieth anniversary of the opening of the Second Vatican Council, Blessed John Paul II wrote: “this catechism will make a very important contribution to that work of renewing the whole life of the Church … I declare it to be a valid and legitimate instrument for ecclesial communion and a sure norm for teaching the faith.”
It is in this sense that that the
Year of Faith will have to see a concerted effort to rediscover and study the fundamental content of the faith that receives its systematic and organic synthesis in the
Catechism of the Catholic Church.
Here, in fact, we see the wealth of teaching that the Church has received, safeguarded and proposed in her two thousand years of history.
From Sacred Scripture to the Fathers of the Church, from theological masters to the saints across the centuries, the Catechism provides a permanent record of the many ways in which the Church has meditated on the faith and made progress in doctrine so as to offer certitude to believers in their lives of faith.
In its very structure, the
Catechism of the Catholic Church follows the development of the faith right up to the great themes of daily life.
On page after page, we find that what is presented here is no theory, but an encounter with a Person who lives within the Church.
The profession of faith is followed by an account of sacramental life, in which Christ is present, operative and continues to build his Church.
Without the liturgy and the sacraments, the profession of faith would lack efficacy, because it would lack the grace which supports Christian witness.
By the same criterion, the teaching of the Catechism on the moral life acquires its full meaning if placed in relationship with faith, liturgy and prayer.
- In this Year, then, the Catechism of the Catholic Church will serve as a tool providing real support for the faith, especially for those concerned with the formation of Christians, so crucial in our cultural context… " UNQUOTE
vatican.va/holy_father/pius_xi/encyclicals/documents/hf_p-xi_enc_19280106_mortalium-animos_en.html
The CCC is easy to understand for anyone over age 15, and contains the Doctrine of the Faith.
They make great Christmas and other occasion gifts.
No Catholic home should be without one.
In 2012 if your Parish or Diocese does not actively encourage the reading of the “CCC 2nd Ed” find out why.