Not knowing the people personally, I do not know the answer to your question. But if they were traditional Catholics, like myself, I may be able to hazard a guess.
The holding of hands is a new development.
Actually, no, that is incorrect. It has been around since at least 1964. It appears to have its origin with the Charismatic Movement (the one that was commented favorably upon by John Paul 2 on more than one occasion).
It has occasioned impassioned commentary over the years; some directed at the bishops, and undoubtedly some directed at Rome. Since it started occurring, Rome has issued not one but two revisions of the General Instructions of the Roman Missal, as well as other documents directed at liturgical actions and postures, particularly to correct what Rome considered improper (e.g. Redemptionis Sacramentum).
For all that Rome has put out concerning the Liturgy, the silence on the issue of holding hands has been deafening. That is to say, Rome has been aware of the issue for decades now, and has seen fit to not comment on the matter. That in itself, given the passage of time and the number of documents issued, should be indicative that it is not a matter that Rome has seen fit to change, institute, revoke, prohibit, modify, allow, or disallow.
Perhaps the comment from Archbishop Chaput (not a bishop one would call liberal) should put people at ease. The essence of his comment was that there was no posture of the hands called for during the Our Father, so it is incorrect to assume, because the rubrics do not call for it, that it is prohibited. Silence on an issue in not prohibition (and before anyone goes goofy and comments about standing on one’s head, holding hands does have some liturgical aspect, as a sign of unity; the former does not).
Further, he said that unless and until Rome speaks, people are free to either hold hands, or not hold hands; those that do should exercise charity towards those who don’t; and those who don’t should exercise charity towards those that do. Meaning, no one should be forced to hold hands, and those who do hold hands are not to be criticized.
Note: the bishop is the liturgical head of his diocese, meaning he has more liturgical authority and know-how than do posters in a forum. And granted that someone can say that he has no authority over another diocese, that does not change the facts of the issue - there is no posture at all required or regulated as to one’s hands during the Our Father.
And as to those who say that it is a novelty, that may be correct to a certain extent; but the same can be said of all the changes that have occurred in the Mass over the last 20 centuries; so the depth of the validity of the claim is perhaps doubtful.