*roll eyes* How can you possibly morally justify piracy?
I'm not saying I don't do it, nor that I think badly of people who do, it is simply not possible to make some justification that it's ethically "ok." You are taking ownership of someone else's possession against their permission. It doesn't matter what the long-term impact on the other party is, the fact that you took from them against their will doesn't change.
Actually, you're not taking ownership of someone else's possession. You're breaching a legal right they have, but you're not actually taking possession of anything they own, nor are you depriving them of anything they own.
The potential legal repercussions are irrelevant, as legal weight and ethical weight are decidedly different. Still, however light the ethical weight may be, the fact that it's wrong doesn't change.
Actually, I'd say it's more legally wrong than ethically wrong.
The principle governing copyright, and originally intellectual property generally, is to incentivize creation and innovation. In patent law, the innovation is one of practical utility, driving growth in technology and so forth. Copyright, however, was intended to give incentives to artists to create their works. It was thought that if you did not give such rights to artists, then they would be unable to produce their artistry and thus the society would be deprived of a cultural asset.
Originally, copyright was set up to last for the life of the author plus fifty years, but the USA essentially forced a change to seventy years when it was realised that the copyright over Mickey Mouse was due to lapse. This retroactive restriction to keep Mickey Mouse out of the public domain has NO ethical justification. It cannot act as an incentive because it applies to works that were already created.
Furthermore, there was not a shortage of cultural work production when the change was made. It's not like potential artists everywhere were saying "Wow, I would spend my time making this new song, but it's only economically exclusively exploitable for fifty years; I need at least another twenty years to make it worth my while to make it.". This was simply the US Government pandering to Disney Ltd., and subsequently the rest of the recording/digital media industries.
As a further erosion, it is now extremely rare for the authors themselves to actually get more than a pittance from sales of their work to consumers. Almost all the time, the bulk of the money is paid to a record company or large conglomerate, who acquire the copyrights from the artist in the first place for a lump sum. Once that lump sum is paid, the impact of piracy on the artist is negligible.
Finally, the empirical evidence shows that the economic copyrights are NOT essential to incentivise people to create. People put their garage band music on YouTube with no commercial prospects all the time. Artists create typically because they are passionate about what they do, not because they see it as a good value proposition. This is emphasised further by the separate legal protection for non-alienable so-called 'moral rights', distinct from the economic rights of 'copyright' which relate to attribution, no false-attribution, no substantial altering (although this one causes problems with the concepts of property; you're not allowed to buy a painting, then alter it yourself, but there's no rule against you destroying your own property so setting fire to the painting would be fine).
So ultimately: these days, particularly with how various governments have expanded it to cover things it shouldn't (computer code, for instance, is protected as a literary work even though that contradicts numerous fundamental principles about copyright) and pandered to special interest groups, typically ones who have failed to protect their intellectual property in the proper means (registered designs, patents), copyright is not only not a particularly strong moral requirement, but can actually be reasonably argued as immoral due to it's widespread use to deprive society access to what it would ordinarily have.
