Several other shows were delayed or chopped up due to earthquake/tsunami-related content too, it's not like Madoka is speshul or anything like that. A J-Pop band even changed the title of their new album from "Killer Wave" because they didn't feel it was appropriate any longer. If that's the way they're feeling, it's the way they're feeling, the TV station included. I guessing there are a few Japanese right now that would rather not think about giant waves at the moment, and THAT'S PERFECTLY REASONABLE.