I have a friend who as far as I know is a capitalist/libertarian, yet who believes that digital piracy is ethically all right if not outright desirable. I find this position somewhat bizarre, and I personally try to avoid copyright-violating theft.
I am not at all opposed to open source. I think it's great to make your work available for free if you can and wish to, and I see a lot of benefits (in software and elsewhere) to doing so.
But, subject to certain limitations (the time limits of patents, fair use, etc.), I think that if you make something, you own it, and have the right to control its use. If I make a CD of the most awesome music ever and I am only willing to sell it for $10,000 per copy, that's my right, even if the price is outrageous.
But what if the record companies are screwing over the musicians such that the musicians hardly see a dime of record sales anyway? Well, frankly, that's not my problem. If Walmart negotiated an unfair deal with a Chinese manufacturer, that doesn't give me the right to steal cheap Chineses goods at Walmart, and I don't see this situation as being any different. Somehow or other, the musicians decided that signing with the label was a good move for them, and until I see evidence that they were coerced or that, for instance, the record labels have some means of preventing you from publishing your own music, it's all kosher as far as property rights go, and I can either buy the CD or do without.
I'm not an absolutist on this issue. I think comp CDs distributed between friends are great and mostly fall within fair use. And I don't have a huge ethical problem with someone copying something they could never afford, like a college student having an illegal copy of Windows. (It's technically wrong in my book, but causes minimal, if any, harm and is completely understandable.)
There is a difference between digital data and physical products, in that the former can be reproduced without cost. If I would never buy a Shania Twain CD but want to pirate one, then I'm not actually costing anyone anything - I'm unfairly using other people's labor, but at no cost to them. If I would never buy an axe but steal one from Home Depot instead, then I am costing them - they have one fewer axe. That difference is why I feel fairly lenient towards small, mild piracy. But it's not enough to make me decide that people who produce digital products shouldn't have the right to charge for their work.