I've thought of the topic of pirating as a corrolary of the free/open-source software movement exemplified by Linux. From the OS kernel up to the most important applications (Open Office, The Gimp, Blender), people among the best programmers in the world have attempted to present a more open side to software, leaning towards the free (but "open" does not equal "free", you can see the difference between the GPL/Stallman's stance via GNU and Linus Torvalds take on the issue). To the point where I've seen many, many times people
expecting software to be free, and of course the data they use, video, music, text files.
The next important element that explains piracy is fairness, or rather the lack of it from the "major" companies that have exploited the unconsciousness of people. I can only give one very big example I personnaly consider disheartening: the creator of the tv series Babylon 5,
J. Michael Straczynski had to give away his rights to taking money from DVDs when he created the series (the studios decide and impose the rules), which until last year made
half a billion dollars of profit and he didn't see a peny, not one. That explains why the authors guild was on the biggest strike ever until a few weeks ago. The problem is the same with CDs and DVDs at an unfair price, with more and more knowledge of the business models of these companies, the customer feels he's cheated by them on the price, the price does not reflect the reality of the cost but is much higher and rather explains their big profit margins.
Of course, there are many other sides to the piracy discussion, but to me free/open-source and fairness explains a large amount of things. It's not about right and wrong, though very often it's wrong (I've attempted as much as I can to buy the DVDs/comics/CDs from stuff I downloaded), it's rather on what becomes (un)acceptable in a social context (look at the silly lawsuits of the RIAA, where grannies were on trial for downloading songs ...).