How would Walmart know? They're not a gaming-centric store, don't have any built in way to 'check game servers', and unless the producers of the game sent them notice, they'd have no idea. A couple people telling a few associates in a store or two wouldn't do anything anyway, the people working in the stores have literally nothing to do with what's being sold. I dunno if I'd trust the person in the article, or whatever random associate he supposedly spoke with about 'hearing from corporate' anyway; seems an easy way to slander a large company online (Not that Walmart doesn't deserve it) when it's likely they are just unaware. Heck, whatever store associate they spoke with was probably lying when an angry customer rolled up and started bitching at him about something he literally had no control over; I had to do the same thing when I worked at Walmart all the time. I mean, yeah, it's crappy, but you couldn't exactly expect Walmart to keep up with this sort of information anyway. Seems more like an honest mistake.
Besides, some of the fault lies with the people buying the game to begin with. You should always do a bit of research before buying anything that costs any amount of money you'd be unhappy to lose if it sucks. A quick internet search would immediately show that the servers are down most likely. I have little sympathy for kids who weren't/aren't being taught to look into things before they buy because it's a good skill to have, or adults who just can't be bothered when buying for a child, because that's just a terrible practice to keep. I mean, this clearly being an unusable product is probably stretching the 'look before you leap' idea a bit thin- but at the same time, why didn't you?