The author states that Wal-Mart employs about 1.2 million people in the U.S., then points out that a lot of them are on some form of public assistance because they aren't paid well enough. There seems to be an underlying assumption here that Wal-Mart would still be employing 1.2 million people if they paid them all more. That simply is not the case at all, and this is proven time and time again in cases where companies or entire industries pay very high wages due to market forces or union agreements.
Apple, for example, generated $171 billion in revenue and $37 billion in profit in 2013. It also pays its employees very well. And yet it only employs about 50,000 workers in the U.S. -- less than 5% of the Wal-Mart employee base.
Now I know the industries are completely different, but what would the author say to the hundreds of thousands of Wal-Mart employees who would lose their jobs just so the company could pay the remaining employees better wages?
If Walmart made a proportionate margin to be able to pay a proportionate wage/salary compared to Apple, this would not be an article about Walmart.