Do you have a source for that? The last time I looked, the USCCB acknowledged that there was a custom in some parts of the US to include women but they stopped short of anything that would explicitly allow it. For the Holy See to allow it in the US, it would first have to be voted upon by the USCCB and then submitted as part of the US adaptations to the GIRM. Forgive me if I am wrong but I have not heard of any of these steps occurring.
Actually, the USCCB did not do that. The reference was to nothing more than a comment printed in a newsletter. That comment has no force-of-law. None whatsoever. It was not the USCCB speaking, but one member of a committee.
So, yes, you’re absolutely right. No such thing happened.
The rubric in the Roman Missal (which is the liturgical law of the Church) specifies men only (meaning adult males). Any variations from that rubric are not permitted. No one, not even a sacerdos (that means bishop or presbyter) may add, remove, or change anything in the liturgy on his own authority (Vatican II SC #22).
Variations from the Roman Missal must be proposed by the Conference of Bishops, and must have the approval of the Holy See form them to be legitimate. This applies unless the Holy See has given prior approval for such changes as sometimes happens by saying things like “unless the Conference determines otherwise” or “unless the Ordinary determines otherwise.” No such provision exists on this topic.
To date, the USCCB has not received permission from the Holy See to modify or adapt the rubrics for Holy Thursday. Therefore, the only legitimate practice is to follow the rubrics as they appear in the Roman Missal.
The only proper interpretation of liturgical laws is one that does exactly what the rubrics state; no more, no less.
There is no “Germanic versus mediterranean” interpretation of the Church’s liturgical laws. No such principle exists in liturgy.
With regard to canon law, there is the principle (see canon 18) that says laws that bind are interpreted strictly while laws that loose are interpreted broadly. Even that, however, is not applicable to this topic because this is a matter of a liturgical law. This isn’t a matter of “binding or loosing.” The Church has often repeated the words of Sacrosanctum Concilium 22.3. “Therefore no other person, even if he be a priest [sacerdos], may add, remove, or change anything in the liturgy on his own authority.” It’s quite clear that there is not a Germanic or Mediterranean way of interpreting those words. They mean exactly what they say they mean.
The variations from the rubrics cannot be called “custom” because the word custom refers to how the law has been legitimately interpreted and applied by competent authority (for a secular parallel, think something like “case law” or “legal precedent”). However, the variations from the rubric are not interpretations of the law, they are instead examples of ignoring the law. It’s an important difference. Even if we do stretch things and call it “custom” it would have to be observed for 30 continuous years—the reason being that it is specifically contrary to the law. Whenever the law is re-stated that 30 year clock resets. The current Roman Missal (for the US) was approved in 2010, so that means that for this to become custom, it has to first be observed continuously all the way to 2040–only then might it be called custom. And even that pre-supposes that the law will never be re-stated. If that happens (a new version of the Missal is approved before 2040) then that 30 year clock begins anew.