Since you are telling everyone what they “need” to do (i.e. “you need to read your catechism” “you need to consult an apologist”). I guess I’ll join in the fun
Rather I believe you should contact an apologist and re-read your catechism.
Here is paragraph 55 of SACROSANCTUM CONCILIUM :
The dogmatic principles which were laid down by the Council of Trent remaining intact (40), communion under both kinds may be granted when the bishops think fit, not only to clerics and religious, but also to the laity, in cases to be determined by the Apostolic See, as, for instance, to the newly ordained in the Mass of their sacred ordination, to the newly professed in the Mass of their religious profession, and to the newly baptized in the Mass which follows their baptism.
If you read the paragraph it is very clear that there are very strict limitations as to when communion under both species can be offered. Why, for example, does it not say: “Communion of both species is hereby permitted in all circumstances” or even “during Sunday Liturgy” ? Instead, it actually points out very, very specific circumstances. It goes so far to give specific examples.
The GIRM paragraph by Vianney only puts another restriction on the reception through the Chalice, no need to mention SACROSANCTUM CONCILIUM there. Also, he mentioned in Italy he never saw the same practice of reception under both kinds there and it seems to be an American practice. This ought to tell you someting. I spent ample time in Italy as well and my experiences were the same.
As for the Catechism section that was quoted. It stated the
sign was more complete. Not that receiving was more complete. The Eucharist is complete in either species.