It all depends on how anal one wishes to get over the issue. It is not in the rubrics.
So, since holding hands during the Our Father is also not in the rubrics, and has been castigated at length and ad nauseum, one could look to those discussions; some would hold that since it is not in the rubrics, it is an “addition” and since we are not allowed to add or subtract anything from the Mass, it is absolutely forbidden.
By that logic, making the sign of the Cross is absolutely forbidden, and to do so is an abuse, which should by all means be reported to the bishop.
On the other hand, there are those who feel that the posture of one’s hands is not regulated at all for parishoners, and that since there is essentially no regulation at all, hand holding is acceptable.
By that logic, making the sign of the Cross is acceptable.
Then again, there are those who hold that a spontaneous hand holding is acceptable, but that the pastor has no authority to require or even suggest that all do so, as that would become a requirement of a posture that is not elucidated in the rubrics, thus getting us back to the issue of adding or subtracting from the Mass, and since this was being done by the priest and the warning to not add or subtract was directed to priests, it applies here and is an abuse. And see, reporting to the bishop.
Then too, we have those critics who chime in that first there is hand holding, and next there will be cart wheels down the isle (as that is not forbidden in the rubrics, as if!) or standing on one’s head (also not forbidden) and thus must be stopped or all sorts of rude and socially unadjustable antics will flow from it, and it must be stopped now. And see, reporting etc.
On the other hand, hand holding seems to have been for low, these forty years and no reports of upside down parishoners or cart wheelers. But then, one just doesn’t know…
And yet there are further issues of serious gravamin, to wit: hand holding is leading some to use the Orans posture, which is mimicing the priest and is absolutely verboten, and a horrible abuse. By this logic, since the priest might bless himelf or others and this too could be seen as mimicing the priest, it must be stamped out to avoid a threat to the dilution of the priesthood and heaven forbid we all know that leads to calls for women’s ordination next, don’t you know, and see the bishop, above and etc.
To which I might comment: the problem with common sense is that it is not all that common.