Bitcoin is not subject to, artificially limited by, nor of value due to copyright. You are not stealing bitcoin, you are stealing the value that bitcoin represents. That value is not some abstract hypothetical potential profit loss but a fairly easy (within a reasonable margin for exchange variation) to quantify amount of spending power in any currency in the world.
If I steal your credit card number (and bitcoin is ultimately nothing more than a secret number that allows you to unlock a persons money and spend it) and then buy something with it I've stolen pretty much the same thing. A number that allows me buy goods using a system that operates entirely on streams of bits.
If I hack your bank account and transfer the money out, that money also is a stream of bits. The same of your paypal account.
These things are unique and set up in such a way that the value, just like an individual tangible CD, can only be possessed by one person.
Software does not actually belong to the guy who holds a copyright in the case of copyright violation the software actually belongs to the guy sharing it and violating the copyright. You can steal a copyright, you can't steal the software. If you copy the software, you both now have copies and nothing is lost from the source. Software that is shared becomes no less functional no matter how much it is shared, software can be possessed by every person and they will all have the same thing with the same intrinsic value.