From Father Zuhlsdorf, of What Does the Prayer Really Say. The "picnic table" refers to the sort of altar used for what an old priest in the 60's called "talking to your neighbor, not to God".
"Today I was strolling and found the Church S. Maria della Pace open. "Miracolo!", quoth I and entered. It is a gem. Standing before the church’s main altar I saw a picnic table pushed to the side of the sanctuary. What really got my attention, however, were a couple of young people looking at the sanctuary and talking about how beautiful it was. I heard one say, "Imagine, for Mass they put that nasty table (tavolaccia) in front of that!" They were all properly disgusted with the idea. The moral of the story? What the aging hippies think they need to do to engage "the people", "the people" don’t want. And today younger people, who are not hauling around the baggage of the ‘60’s don’t want what the hep-cats have pushed on us for years. "
But times are changing rapidly. I think we will see more and more younger priests ridding their churches of iron-boards and re-orienting the Mass once again. We are getting constant hints that this is path of the future. I am guessing the Holy Father might even talk more about this in a document."