I've tried to figure out where that attitude came from. Most of the Corinthians were probably pagans. They had sacrificial meals (so did the Jews). The priests got some, the worshipers got some which they took home to cook, and what the priests didn't need was sold. There were probably some community festivals (and potlucks), but I can't recall any offhand. The temples were small.
When did excess meat become "desacralized?" Knowing that some of the offering would become profane may have made the rest seem a little bit profaned too. Maybe.
Most offerings had to have been cooked and eaten at home (no room at the temple!)--I'd guess these would be mostly family gatherings, where you don't have to consider whether somebody else is rich or poor, you just do what you've always done.
So if they considered the Lord's Supper as a larger meal, and brought in attitudes of "less than fully sacred" and "eating just like at home," the result could be pretty unedifying to the larger family.