You are making a false equivalence between different kinds of copyright violations. Private individuals downloading copyrighted music for non-commercial use is against copyright law. But it doesn't deprive musicians of much (if any) income, since they make most of their income from performance and merchandise sales anyway. But when a magazine publishes articles from a writer without attribution, they are profiting off the writer's work and depriving her of the income (since selling articles to magazines for publication is how a lot of writers earn their living).
Granted, this magazine was a shoestring operation, not some big multinational conglomerate that had a legal team to cover all the ins-and-outs of copyright law. If they had legal advice or a decent understanding of copyright law, they obviously wouldn't have done this. But that's just the thing: music companies are suing private individuals who accidentally shared a few songs, and getting hundreds of thousands of dollars of damages. Their ignorance of copyright law doesn't get them out of jail free.
And just to be clear, I think copyright law should be abolished, and replaced with a requirement for attribution. I think downloading music and movies is fine, and artists should find a new way to make a living, because charging for copies is untenable now. But I think artists, writers, etc. should get credit for their work. So I think it would be fine to take a book, change the last paragraph because you don't like the original ending, and publish it, as long as you make it clear that it's a derivative work. So you might not agree with my opinion, but it's perfectly consistent to be for non-commercial downloading, but also against magazines ripping off writers.
I am also sick of the "slashdot thinks X and slashdot thinks Y, so slashdot is a bunch of hypocrites" line of reasoning that crops up on almost every copyright story. slashdot is made up of hundreds of thousands of people. Maybe the people who are all for downloading are mostly different from the people are against ripping off writers. Or maybe most people think non-commercial downloading is OK, but ripping off a writer for commercial gain isn't. Who knows? If you want to accuse a person of hypocrisy, go ahead. But slashdot isn't a coherent entity to have an argument with, and it doesn't have to have a consistent opinion on anything.