It isn't that they actually put it on devices, it was put in everyone's cloud. Considering some people pay for icloud storage, having something in their that you don't want is annoying. If you don't pay for extra cloud storage, it is still taking up space in your free storage. You have to pay for iTunes match, which is the only way you can delete songs/albums in the cloud that you no longer want. Without that, you would have been stuck with the U2 album in the cloud until they put out the "patch" to get rid of it.
Personally, since I am not a U2 fan, I view this essentially as junk mail. I have been sent something I didn't want and now it is my problem to dispose of it. Not that big of a deal, but it is annoying. If I had wanted this album, it isn't that difficult to go to iTunes store and download it. That would have made it more like a guy handing out flyers. If you want one, you take it. Otherwise, you just move on without being inconvenienced.