This meme needs to die [1]. A fisherman doesn't care that a dolphin isn't a fish - when he calls it that, he means that it swims in the sea, gets caught in his net, and tastes delicious. Similarly, Murdoch's perspective is that of the copyright investor - he sees the purpose of copyright law as creating and protecting a new class of property in order to encourage its production. His assets are invested in the production of this "new-style-property" which the federal government promised to protect (just as it does material property). From his point of view, the nature of distribution of that property just aren't relevant.
1. The cognitive bias is so painfully blatant: "the guy I disagree with is a liar bullshitting idiots, or is an idiot himself"? Come on.