I'm saying there was no intent to deprive someone of access to something they already own, or are in possession of. There might be intent to not pay for a licence to access something -- but not paying isn't the same as stealing. Everyone else still have access to their licences and licensed copies.]
Legally, theft means you deprive someone of their access to a thing. There's a difference between that, and "getting something for free that you should pay for" -- when that 'thing' isn't a thing at all -- it's a copy -- and by the act of copying you aren't depriving anyone of their access to the thing you copied.
If you steal a book, you're staling it from the current owner: either an avid book fan, a shop, a library. On very rare occasions, say at a conference -- the owner of the book-thing will happen to be the same legal entity as the author (tough even more seldom the copyright holder, as that might be the publisher).
I'm not saying that copyright infringement is legal, I'm saying it's not theft.
On a side note, the use of the word piracy is even worse -- it implies threats and/or application of violence -- effectively lifting something that is a civil matter to a criminal matter.
> in common parlance, taking something without permission is theft, even if it's not tangible property (e.g. "he stole my idea".)
And you can also call "a bargain" "a steal". That doesn't mean it's illegal to shop at a fire sale...