And yes, by altar servettes, I meant altar girls (I forget where I saw that term coined, but it amuses me

). Girls cannot be clerics, so they should not be permitted to assist at the Mass, period. This is really non-negotiable in nature.
The supreme legislative authority in the Church has decreed that girls/women can fulfill both the roles of reading at the liturgy and of serving at the altar and, as is said in canon law, that is beyond appeal now.
Canon 333 §3. “No appeal or recourse is permitted against a sentence or decree of the Roman Pontiff.”
A canonical
dubium was submitted in petition to the Holy Father for clarification. The Holy Father made the clarification. He issued a decree, which was published by the Pontifical Commission for the Interpretation of Legislative Texts.
A future pope can change it, since it is discipline, but no one can say that it is outside the pope’s prerogative to legislate in favour of it. To be clear: a bishop may opt not to have it. If the diocesan bishop opts to allow it, a priest celebrating Mass may opt not to have it. But for those of us who do allow it, the lawfulness of a girl or woman doing these functions at the liturgy is without question.
Serving at the altar, even by an instituted acolyte who is a seminarian, is a lay function. It is simply not a clerical function…and it predominantly has not been.
Beyond these points, as a priest and theologian, I could not be more in agreement with the decree of Blessed Paul VI. It was a welcomed and needed clarification. Ordination in the Roman Church is now intrinsically tied to the Sacrament of Holy Order. There are no longer lesser ordinations. In the same way, the concept of a cleric is now intrinsically and clearly tied to being ordained and to having received the Sacrament of Holy Order.
The Holy Father, Blessed Paul VI, did the same thing at the next level up and this has been continued by his successors. At the head of a collective of the lay faithful should be a bishop. Not some other category of ecclesiastic. We had other mechanisms in the past…and they were seen in both the United States and Canada, for example, as throughout Europe. We had Abbots Nullius governing territories of the lay faithful and the secular clergy, with their own jurisdictions, in place of a bishop.
This sort of arrangement has slowly and progressively been suppressed…even at Monte Cassino itself. The United States lost its instance of this in the 1970s and Canada just a few years ago.
The secular and the lay faithful properly should be attached to a diocese, which is properly governed by a bishop, according to contemporary principles of a sound ecclesiology. We still have Vicars Apostolic and Prefects Apostolic but they operate in mission lands and only until the first moment when a diocese can be erected.
The present arrangements are much cleaner theologically. As we read in the Dogmatic Constitution on the Church,
Lumen Gentium, there are those who are lay, there are those who are consecrated (in some form of consecrated life) and there are those who are ordained. Seminarians, until they are ordained deacon, are to be counted as lay men. In the norm, portions of the People of God are under the care of Bishops, who are their shepherds.
As Blessed Paul VI decreed, the stable ministries of lector and acolyte can be imparted to lay men…those preparing for Holy Order must receive and exercise them. But also, as in antiquity, those who are not destined for Holy Order may receive them – and frankly, should. Those who exercise these ministries in an uninstituted fashion are doing so because an instituted minister is unavailable…it is a temporary solution of deputing someone to act in the absence of an instituted minister.
Fortunately, there are places that, albeit slowly, are implementing
Ministeria quaedam as it concerns the stable ministries being given to lay men who are not candidates for Holy Order. This needs to be driven forward. As also the establishment of new stable ministries, also called for by
Ministeria quaedam, according to the opportunities that could benefit the Particular Churches, diffused throughout the world.
From the perspective of theology, I hope, as things go forward, that clarification is made in attire so that clergy always have the opportunity to dress as clergy (when appropriate) and that those who are not clergy are able to be distinguished from those who are. This is still an evolving situation but one that ultimately should and needs to be addressed.
The duty of distributing communion at Mass must be reserved to priest alone (and deacon).
As a priest, I am most grateful that the Church has disposed otherwise and, as a priest, I gladly cooperate with those dispositions.