On the surface this looks bad, but let me walk you through a little scenario:
You're a small company, making cars and selling them as well as other people's cars. When you sell other people's cars, you ask for a cut, since you pay for the fuel, advertise for them, let them sell their accessories in your stores. They give you this cut because you're providing a valuable service, and your customers love how they're treated in your store so are very loyal and trust brands you recommend.
One of the bigger car makers decides to sell one of their custom cars in your store. They give the car for free, so they don't have to pay you anything for access to your loyal clients or for the space their cars take. They can afford to offer it for free because the fuel and accessories for it are only available from their own showrooms, and each car comes with instructions on how to get to their showroom.
Tell me, would you keep "selling" their cars, when it's obvious that they're just a vehicle to get people to go to a competing store?
Now lets look at Apple. They host the apps, they provide the download bandwidth, they advertise, they have the trusted environment, they have the loyal audience. Some companies have worked out that if they give the apps away for free, but include a link to a web site to sell content, they can lure these loyal customers to their stores without giving Apple anything for the service. These greedy companies want 100% of your money, and the ability to get all your details (that Apple protects strongly) by using their own sales portals.
Tell me now if you wouldn't kick Sony and others out of your store for the same behavior!?
Apple offers a lot, and only asks for 30% of an electronic sale that has very little direct cost to the sellers, but still many companies strive to find ways to deny Apple that 30% that they use to keep the store running.