Hi Take, (great name by the way)
Actually it is not Walmart that does anything to edit orcensorthe CD. The Record Label actually puts out edited (clean) versions of certain CD's. Now is that because Walmart (who has 20% of all record sales) wants to sell edited versions to their customers which forces the labels to produce these edited versions? possibly
I don't view walmart as engaging in censorship as much as I see them offering CD's to kids who are not allowed to listen to the unedited version either because they themselves don't want to hear that language or because their parents won't let them buy the CD otherwise.
The labels also produce these edited versions for the radio stations who do not play vulgar lyrics.