If you still want to try and defend Wal-Mart, then maybe give a read of Wal-Mart's Labor Problem and think about it.
With the exception of a billion where it should say million (the article states each individual store is worth $204 billion but that's just a little outrageous), the article does a pretty thorough job of exposing just how much Wal-Mart sucks.
From income discrepancies to violations of Fair Labor Standards Act to The Family Medical Leave Act violations to union busting to deplorable health care coverage to discrimination. Its all there with references.
Read it and draw your own conclusions.