I maintain my position: mixes and mashups are not original, "innovative" works. They're entirely derivative. They might be "creative," but that's not the same thing. I also don't believe that they constitute any sort of "fair use," and so they're common theft and should be treated accordingly.
It's interesting how the "artist" in this Techdirt story talks about how much his albums would cost if he were required to pay royalties to all the copyright holders he steals from. Interesting concept.