By Peter Coy and Susan Berfield
The public images of low-paying employers such as Wal-Mart and McDonald’s take a hit during the holidays, when Americans are seized by a spirit of charity. Stephen Colbert mocked Wal-Mart after employees at one of its stores started a Thanksgiving food drive for fellow workers. “Now, some critics out there say Wal-Mart isn’t doing enough, but they’re wrong,” Colbert said, “because Wal-Mart isn’t doing anything.”