Wal-Mart is changing its marketing emphasis to serve different customer bases. For example, urban, hispanic, rural. Part of this change is due to its growth into areas that are different from its original markets, which were primarily rural. This explains the replacement, for example, of guns with home fitness products. In some markets, they will be employing consumer electronics specialists called "know-it-alls" to serve markets where electronics are big.
The issue of Wal-Mart dropping guns from some stores appears to be due to the company's expansion, and not due to an anti-gun bias.
This summarizes an article in today's Wall Street Journal.