I agree with you. Several months ago I listened to a lawyer who is an IP expert make the case on The Jason Stapleton Program that there is actually no such thing as IP (I'm sorry I don't have a link). I was fascinated by the discussion. Without trying to remember all the details of his arguments, he basically made the distinction between real (i.e. tangible) things versus abstractions like intellectual property.

Basically it comes down to the difference between theft and fraud. You can't steal someone's idea (like a song or story) that they voluntarily introduce into the public domain because those things aren't physical, or "real". But you can commit fraud (a violation of the NAP) by attempting to pass off someone else's work as your own.