Jim Glassman at TCS has a really good column on the topic. He writes:
....25,000 people would prefer to work in those jobs than the jobs they have — or don't have — at the moment.
That's the fundamental fact of economics that the critics seem not to get. Sure, for those with college educations or substantial technical skills in high demand in the marketplace, work as a stocker or cashier in the retail industry would be undesirable. It's hard, stressful work. But there would appear to be 25,000 people out there who consider those jobs a step up from where they are now.
Perhaps all those who moralize about Wal-Mart's evil labor practices ought to consider how people who might actually work there feel about it, before attempting to legislate Wal-Mart out of town.