Holding hands is like a halftime show or commercial break in the Mass.  

The Holy Eucharist has been consecrated and is on the altar, the Great Amen has been sung, we are about to "dare to say" the prayer Jesus taught us, then chant the Agnus Dei, then kneel and (echoing the words of the centurion in the Gospel, and the priest in the older form of the Mass: "Domine non sum dignus...") declare our own unworthiness, then finally to receive the Eucharist if we are so disposed.  

But between that Amen and the Agnus Dei, let's ignore the Blessed Sacrament for a moment and hold hands like hippies and have a kind of dime-store, chinese-knockoff communion.  No thanks!  

When I was growing up this was imposed on us one Sunday in the late '80s at the prompting of some laity who didn't think too hard about it or realize that they were desacralizing the Mass.  It is good that this practice is fading out and that our sense of the sacred is returning.