I'm hoping that you're merely explaining the policy rather than defending it. Apple sells iTunes content while trumpeting promises that the user can stream purchased content from the cloud to Apple devices. For example, I know someone who purchased a season of The Legend of Korra from iTunes to stream from their Apple TV, but who uses a laptop and doesn't have storage space for all the many movies, songs and programs they've purchased. I myself have purchased and downloaded both of the first two seasons ($80) and have them all safely downloaded on my computer, but I still feel that I've lost something by losing the ability to stream remotely when I'm away from my primary iTunes library.
You are correct in this: when we purchase iTunes content, it can be taken away for any reason, without explanation. Although we are forced to accept those terms when we purchase content via iTunes, taking our money and then taking away the things we've purchased -- well, that's theft. We didn't agree to be robbed, but Apple did in fact warn us that we *could* be robbed if either they or the content providers felt like it. It's hard, I think, for the average person to understand just how little either Apple or Viacom cares about our feelings once they've got our cash in-hand. I've been trying to get the courtesy of a simple explanation from either Apple or any number of Nickelodeon reps over the past two weeks. No answers - Apple says they know nothing, and Nick can't even be troubled to respond with a simple yes/no as to whether the removal (from the U.S. store *only*) is intentional.
Right now Nick / Viacom is playing games; they're in bed with Amazon and I expect that has something to do with this. Google "Legend of Korra - Book 3" and you'll see that this has been a mismanaged catastrophe from day one; Nickelodeon appears to be dumping the season as quickly as possible due to online leaks back in the late spring.
It's too bad - it's a great show, and my two daughters love it. But they will have to do without. I will never, EVER intentionally put another penny in Viacom's pocket after this coy little game they've decided to play. If they don't want my money, I'll be glad to spend it elsewhere.