Just because it's tacky doesn't mean it's bad:

The magnitude of the benefit [Wal-Mart brings to the economy] is enormous. Hausman looked at food, and for that category alone Wal-Mart increases consumer welfare by 25 percent ... Since food is about 12 percent of GDP, multiplying .25 by .12 gives a benefit of .03, or 3 percent of GDP from Wal-Mart.

This tracks well with what I've read in other publications. Keep it in mind the next time some left-leaning pundit tries slashing Wal-Mart for its various practices.