I fail to see the story here. The welfare-to-work tax credit has been in effect since Welfare Reform was implemented in the late 90's. I can guarantee you Walmart is not the only company to take up this opportunity nor are they the only one's to keep wages and benefits minimal. There are multiple companies, including Marriott. At least these people are working.
I, for one, would not pay the workers at Walmart any more money than they are getting. Having the worst customer service, per a survey of national companies, says it all. Yes maybe the company doesn't train them in this but it is something that is common sense. It doesn't take a brain surgeon to know that when someone asks where something is located you don't just walk by and point.