Holding hands during the Pater is some sort of Protestant custom imported by Charismatics. I don't think you can really blame the bishops for it, except to the extent that they've tolerated it or given a bad example by doing it themselves.
And no, it's not required, and it's wrong to try to impose it on people -- even if it's lay people imposing it on other lay people.
We never held hands when I was Protestant, but then, it was Presbyterian, and rather stiff. However, I’ve never been in a Catholic parish that did not, although I’ve probably visited some. Doesn’t bother me either way. I’m nearly always holding onto my kids, anyway.