[jkn]

I don't see any justifiable reason why this shouldn't be illegal

Because sharing is good and it's not our problem if the currently dominant business model has troubles with it?

Even if you think that sharing music freely should not be allowed, the fact remains that we are dealing with an industry that refuses to adapt to new technologies and new customer expectations, and engages in despicable conduct to preserve their outdated business model, as this story illustrates. In this view, accelerating the change, or doom, of this industry is rendering a service to society. Letting them go after file sharers is simply helping them resist change, and only by fighting the symptoms (we're losing some sales) rather than the causes (it's easier to "pirate" than to download legally, legal downloads are too expensive and impose unwanted restrictions).