I'm not sure what the point of this particular semantic debate is. It's not theft. Ok. It's still wrong, it's still harmful, and it's still totally within the purview of a reasonable government to regulate or outlaw.
Would copyright infringement still seem intuitively, morally wrong, if there were no copyright laws to begin with? If creators were never promised a legal expectation of control over their work, would you be violating any legitimate expectation by copying? Let's say that someone produces a musical album, and, knowing they cannot legally stop you from downloading it, they ask you not to copy it unless you send them $5…
I think this is a one problem. In the internet almost anything is public good. It's available for almost everyone and you cannot or you don't want to shut people of from consuming.
Not related, but the second problem of the copyright is that it's hard and expensive to use it properly. If you would want to legally use a song in your presentation, make a mixtape or even sing a song on your mom's birthday, you would have to go through riias, companys, individual artists, lawyers and applications to get proper rights.
Above process is fine for big corporations, they have the time, money and maybe motivation to do this. Individuals don't have this luxury. We all know that singing that song for your mom is copyright infringement, therefore as mattmaroon says, theft, don't we?