Laibach is a post-modern art/performance band or group. They take songs, symbols, and cultural references from the mix, take them apart, and put them back together in order to make points about society, at the beginning about Yugoslav society but, since Yugoslavia's breakup increasingly about broader themes, including the civil wars in the ex-Yugoslav states. Because their music is very harsh they're usually called industrial, as is the case for other reasons, but they're really just artists. As Ivan Novak, a founding member of Laibach, said in Seattle last year at the opening of the NSK exhibit at the Frye Museum of Art, they're not "cover songs", this is not Laibach "covering" a song but instead reworking it and giving it a new meaning, which, of course, is by no means easily apparent from a casual listening of the the songs themselves.
NSK, which has the visual art component of this whole thing, IRWIN, much more obviously takes from different symbolic traditions and reassembles them into something new. The evidence of it, of course, is right in front of you in the forms of collage and paintings which in themselves combine very obviously different symbols. Laibach's music, on the other hand, can be listened to without one guessing that they're messing with the meanings of the songs; this of course leads to false ideas about what they're trying to say but, as the band says, they function somewhat as a mirror, by which they mean that since they deal with symbols and popular culture that if you listen to their songs with no idea what they're about your reading of them is likely to be more reflective of you than of them.