Practical distinction:
Copyright infringement is only recoverable in civil law. It is not criminal (as has been pointed out), and you can only recover damages. For one bootleg copy, probably not much, if any, damages will be recovered.
Theft is a crime, which may result in jail.
This, in itself, is already significant - they are trying to give a civil wrong a criminal air. Do you think a parking ticket is a crime? Do you feel like a criminal? This “criminal feeling” is vastly important. Now, if you think that copyright infringement is in itself a bad thing, you might think that “criminalising” it would be a good thing. Why hasn’t the government done it yet? It might be useful to look at the historic use of the copyright.
As you admit, in the law, they are not the same. The issues involved in both are vastly different, and should not be confused with one another. As someone else has said, copyright was made so that innovative material would be available to the public, in the same vein as patents, and the author would be rewarded.
However, both copyright and patent are limited in time, copyright much more so than patent: a copyright does not protect the idea, but merely the expression of the idea. This is to ensure that this material will eventually benefit all of mankind, rather than concentrate the benefits in the hands of a few, or to allow the author to destroy it for all future generations. In fact, when patents and copyright is registered, a description has to be made public, as all of you who have trawled through the patents office will attest.
This is what the companies are trying to get around by using “theft” to describe copyright infringement. They are trying to imply that you have no right to the copyrighted material, that they, and only they, can decide what happens to the material.
As some on you on this thread are already thinking.
In reality, you could make copies of everything on earth, if you paid the damages. That’s what copyright is for: allowing the holder of the copyright compensation, while making the material available to all. I’m not talking about piracy; there is a difference here. I’m talking about one copy, for your personal use, not for economic gain. In normal cases, it would be called “buying a copy”.
Incidentally, that’s why you do not appropriate the right to reproduce: you simply owe damages, not assume the right of reproduction. What a copyright is, is a tool to ensure that the holder of the copyright is compensated when copies of the work are made.
And then, after all that, you have the problem of large corporations (music industry, I’m looking at you) who don’t compensate artists very much at all, and who own the copyright to the music which the artists produce. Do you think giving them more power to control what music you get to hear is good?
You might then ask why artists sign away their copyright in the frist place, if they aren’t really getting much in the form of royalties. That’s because the record companies have the distribution networks, and artists need the exposure. Courtney Love, on copyright.
Now, think about the soundbite “Copyright infringement is theft” again. Not so simple.