Jhymn (Windows and MacOSX version of Hymn which was a command line program) both violate Apple's license agreement when purchasing iTunes music. That being said, Jhymn doesn't work with iTune 6, it only works with earlier versions of iTunes. To make it even more difficult, Apple programmed iTunes 6 so that once you buy music using this version, you cannot downgrade to an earlier version of iTunes and continue to purchase music. At this point you are now locked into iTunes 6.0 and therefore unable to use Jhymn.

So there's a legality issue, plus Apple is ahead of Jhymn in encryption game. It's somewhat stupid considering you can bypass the encryption simply by burning and ripping using Apple's own iTunes software.