The closest Wal Mart to me is roughly 20 miles. I have been curious about them and kinda would like to go check one out, but I belong to a union so of course I would hate myself for going.
Here in the SF bay area we have many other opportunities for decent pricing anyway, so I don't really feel the need to get into a Wal Mart store.
I certainly do not fault anyone for shopping there. And if you need to, you should shop there happily and proudly. You gotta survive and feed yourself and your family.
I suppose some of the other stores are really not much better. It is just that Wal Mart is the biggest and most aggressive at what it does and therefore any effect it has on communities etc. , or the trends that it sets for other businesses to follow have a stronger impact than that of smaller merchants.