Playing South Park on Apple TV through iCloud
I am having this issue as well, and have been experiencing the problem for a while now with my gen 2 Apple TV. I just picked up the new Apple TV this morning, and assumed the problem might correct itself with the updated hardware. I was wrong. I am able to stream all my TV shows and Movies purchased through iTunes through iCloud, with the exception of anything from South Park. I just got off the phone with AppleCare, and they referred my case to a senior specialist and gave me a case # and told me to email the iTunes store directly and describe the problem. I am waiting to hear back from them. I will keep you posted.
My suggestion to you (or anyone else experiencing the same problem) is call up AppleCare and tell them you are having the same problem and get a case # and then contact iTunes directly. The more case #s they have reporting the same problem, the more likely they are to resolve the issue in a timely manner.
In the meantime, if you have an iPhone, iPod Touch, or iPad, and you want to play South Park from iCloud without having to use iTunes home sharing, you can play the episodes on your iDevice of choice from the cloud, and then use AirPlay to play it on the Apple TV. It works for me, but it's not as seamless as just being able to play it directly from iCloud onto the Apple TV.