does anyone else find it frustrating that
/.ers are in favor of unlimited property rights except when they go digital
First of all, slashdot is not a monolith. Different people will pipe up in different conversations to say their bit.
Second, there is a fundamental difference between physical property rights and intellectual property rights. The former is inherently scarce (e.g. if you force Apple to do X with its money, it can't do Y with the same money, in general). The latter is not (e.g. my copy of an ebook did not prohibit anyone else from having a copy of an ebook).
This is why some people (I'm not necessarily among them) object to using the word "stealing" to refer to copyright infringement. A copyright holder doesn't "lose" money when someone downloads content illegally, but they do, potentially, lose a sale. For some industries this distinction is important (various professional-level software packages don't bother pursuing pirates, because they know that it will increase its market share to sell to their real customers, the businesses which will pay hundreds for a software package).
Keep in mind that the purpose of intellectual property laws (patents and copyrights) is to encourage innovation. A temporary monopoly gives people a (greater) incentive to create original works, knowing that they can try to extract value from their creations. This inherently limits the rights of others, who would otherwise be able to use and build upon works in the public domain.
The trouble is that this model has been breaking down on a few levels from its original intent. The first is that copyright extensions have kept works from entering the public domain for quite some time. The second is that patents on some inventions, especially software, are/were often granted with too little deference (one can argue) to prior art and "obviousness". Instead of encouraging innovation by small players, big companies amass patents in a kind of cold war against other big companies, and keep small businesses from being able to enter (because in many industries it's basically impossible not to be sued for patent infringement for something). You see entire company purchases made just for the building up of patent portfolios (arguably a large part of Google acquiring Motorola, for example). This isn't innovation, it's a new cost to doing business in these industries.
Do I subscribe to all of the above? No. But it's not inconsistent to strongly believe in physical property rights but think that intellectual property rights have gone too far.
Finally, it's fine to argue that wealth inequality is not an ideal outcome. To describe it as "pre Renaissance" is to imply heading into the dark ages. Within the western world, even fairly poor people live much better than the richest of that era, by most reasonable measures. To say that "all anybody cares about is the Beatles" when the news is plastered with the Occupy Wall Street protests rings pretty hollow to my ears.