Good points. The second link is excellent, may incorporate into a revised version of the post.

But in addition to the points it makes, there's what seems to be a questionable moral assumption here: even if Walmart could pay employees more by taking a hit in profits, why should they bear that burden alone, as opposed to spreading the cost of improving those people's lives over the wealthy as a whole through taxes? That's where the anti-Walmart crowd seems to assume something like, "hiring someone creates a (fairly) strong moral obligation to look after their welfare, above and beyond things like not cheating them."