And why do people stop shopping at them? Because of the above reasons.
Perhaps, if you really feel that way, you should rent a bit of land down the street from Wal-Mart (or stand on the public ROW next to the street), and display a large sign, informing people why it is detrimental to them, in the long run, to shop at Wal-Mart. Instead, people like you just bitch, whine and moan, and after that's not enough to do anything, you try to bully the local government into disallowing Wal-Mart's attempts to compete. I don't shop at Wal-Mart. There are six Wal-Marts within ten miles of here, yet other grocery stores, hardware stores, and other Mom & Pop businesses still exist. And this is in Wal-Mart's back yard, where lots of people really are poor. Don't give me that crap.
When you see Wal-Mart using predatory pricing tactics, yell loudly it. Most of the time, you don't see them pulling that crap, because on the national level, they don't have to resort to such things to compete. Hell, I've been to many Wal-Marts where other stores in town are selling goods for much cheaper than they are. Are those other stores pricing their products in a predatory manner? Perhaps the government should just regulate prices on everything, then it will all be about efficency.