There are some zealots, I admit, who really do believe that authors should release books for free and copyright shouldn't exist at all, or that all software should be free. Putting aside the question of 'if it's free, you are unlikely to make money on it, and there's no incentive to actually work on it as opposed to getting a different job,' there are other considerations.
Without copyright, for instance, someone could take a book and decide they want to publish their own version of it. They alter it -- cutting scenes, and adding a few they think are better -- and release their own revised edition with the same byline. The author's message is no longer there, and you no longer have any guarantee that you're getting the actual /book/ and not just someone's mutant edited copy.
Add to that the fact that our copyright laws were specifically altered some time ago to adhere to the Berne Convention guidelines, so that our copyright would be enforced and upheld by other countries who are signatories to it.
Really, what it boils down to, I think, is that the majority of people who pirate stuff do it because it's simple (just download something!) and it's free (and people are all about the free stuff). And all the arguments about how it 'doesn't hurt anyone' or how it 'only hurts the publishers' are largely just justifications. And 'I wouldn't have bought it anyway' doesn't really count for anything. If you wouldn't have bought it anyway, that's no excuse for theft. Hey, I wouldn't have bought that DVD player, but that makes it okay to steal it! Bzzt.
If you can convince yourself you're taking a Moral Stand against Big Business or whatever, you don't have to think about the fact that you are stealing from the people who wrote that game you're enjoying so much, that piece of software you use every day, composed and performed those songs you just downloaded in MP3, or wrote that book you just downloaded in eBook format.
The immaturity shows in a number of ways in the pirate community. Witness people who cheerfully accept acclaim and praise for making pirated goods available; the eBook scanners who cheerily accept the acclaim and thanks of the various pirates, acting as if the books were their own work. Hell, think about our Russian hacker friends who have an entire site devoted to Trillian as if it were their work, when all they're doing is distributing pirated copies of Trillian Pro and plugins.
I'm halfway tempted to talk to some of the authors, game developers and so on who I know, and ask them each to write a short essay on copyright and piracy, and collect them into a freely-available eBook to distribute on the net...