The position you outline is, substantially, correct.
Personally, although I have had American students, I have never understood how certain Americans become almost obsessive about rubrics. It is bizarre. I had hoped that the need for the CDW to intervene some years ago would be so chastening that it would lead to a change of this disposition.
To a dubium originating with Cardinal George, there was a wonderful answer to clarify the nature of rubrics for the laity. It is worth quoting substantially:
“Numerous inquiries” received by the BCL led Cardinal Francis George, chairman of the BCL, to submit a dubium (doubt, question) to the Holy See’s Congregation for Divine Worship and the Discipline of the Sacraments (CDW) on May 26, 2003:
Dubium: In many places, the faithful are accustomed to kneeling or sitting in personal prayer upon returning to their places after having individually received Holy Communion during Mass. Is it the intention of the Missale Romanum, editio typica tertia, to forbid this practice?
Cardinal Francis Arinze, Prefect of the CDW, responded to the question on June 5, 2003 (Prot. N. 855/03/L):
Responsum: Negative, et ad mensum [No, for this reason]. The mens [reasoning] is that the prescription of the Institutio Generalis Missalis Romani, no. 43, is intended, on the one hand, to ensure within broad limits a certain uniformity of posture within the congregation for the various parts of the celebration of Holy Mass, and on the other, to not regulate posture rigidly in such a way that those who wish to kneel or sit would no longer be free.
The BCL Newsletter continues: “In the implementation of the General Instruction of the Roman Missal, therefore, posture should not be regulated so rigidly as to forbid individual communicants from kneeling or sitting when returning from having received Holy Communion” (p. 26. emphasis added.)
Indeed, this principle applies here, as well. The directive for the laity is to stand for the Our Father and what follows. Of course, the laity are free to choose another position, if common sense directs it…one who is ill or otherwise disabled, one who is aged, one who is holding in hand or nursing an infant…may be unable to stand or it may simply be better for them not to stand. Whether their hands are folded or are palm-against-palm or resting on the pew in front of them or behind their back or are at their side or are holding someone else’s hand or are elevated in the orans posture or otherwise occupied is the concern of the lay person…it is not the occupation of the rubrics. It would be to go into the arena of rigidity which Cardinal Arinze – and others – rightly condemn.