If Wal-Mart owes no obligations to the community, then why censor the material? It sells, it makes a profit, and as a publicly held company, the directors owe a duty to the owners (stock holders)of the company to generate revenue. Now, although there is no real way to interfere with business decisions (if you don't like the directors, sell the stock or vote them out) it doesn't sound like they are making a decision based on business, but on morale character. Or is it? Is this a marketing tactic to appeal to middle America and the Bible belt? Is this a calculated decision to bring the message "Shop with us because we have strong moral character" to the average consumer, so that they, in turn, feel that by shopping there, they are demonstrating strong moral character? Is this not, possibly, a business decision beyond that of merely deciding what monthly mag to put on the shelves?
Which brings us back to the fact that they sell guns...why is it that violence is okay in this country and sex is so reviled? Without going too deeply into it (Lenny Bruce and George Carlin do a much better job than I ever could dream of doing) it seems that if you're gonna pull something that glorifies sex, pull magazines that glorify violence as well. Do we really need more copies of Soldier of Fortune floating around? Or, again, does it turn back to the "image" issue behind a simple business decision. Does it need to be fair? Nope...life's not fair. It sucks. get a helmet.
Does Walmart owe a duty in rural areas to the population? Are the products that they are cutting off truly essential (Cosmo? essential? reality check!?!) as opposed to guns (as difficult as it is to believe in our little urban section of the world, there are sections of the country that believe in hunting for their own meat...as archaic as this sounds, if you worked on a cattle ranch and saw what they fed to them, you probably wouldn't eat it either...)
Will we ever know why they are doing what they do? The company almost singlehandedly drove K-Mart out of business (their plan for the longest time was simply to open a Wal-Mart wherever there was a K-Mart, and then undersell them until they went out of business) and does have an enormous impact on local businesses (although one town I lived in saw an INCREASE in business into their town center from the traffic - so it's not always a negative impact) but it's a business. And the argument that applies to censorship (just don't watch/listen/acknowledge it) applies to the business.
Why are there so many mindless reality shows on? People watch. Why is there a Wal-Mart? People shop. Why did they develop New Coke? because there were morons in charge...
Just my 2-cents