Seems to me that while people are okay with the abstract notion of libertarianism, they also have these notions about how people should be able to earn a living wage doing what thy want to do, and that small Mom and Pop stores should be able to continue doing business even if it means that extraordinary legal measures have to be taken to keep Wal-Mart out of the neighborhood. This reminds me of the comment Garrison Keillor makes in Lake Wobegon Days about how his neighbors talked a lot about free enterprise but in practice expected people to support each other by buying local, even if it was less expensive to buy things a few miles down the road in St. Cloud. You see this on a bigger scale as subtext in Neil Stephenson's Snow Crash, where laissez-faire capitalism run amok has broken up the United States into "franchulates" and "Burbclaves" and some random scattered pieces of "Fedland" where the old Federal government still exercises what little power it still has. (Economically illiterate, imao, but that's an argument for another day.)
Now, I'm not going to repeat the normal arguments in support of Wal-Mart; you can find some here and here. These also apply to the other category killers, though WM tends to attract most of the flak on account of their high visibility and conscious Low Rent approach. There are conservative arguments against WM, too. What I want to know is, what's the libertarian argument against the big box stores? Is there one? Or is this just a case of people (as usual) being people and having different political stances on different issues?