If by the time you click this slightly NSFW link, it takes you to one of those sad "this video has been removed" notices instead of a hilarious Hitler-reacts-to-something parody, blame Constantin Films. They made "Downfall," and they've called for the parodies to be pulled. "Hitler-reacts-to" videos have become an internet institution, as much as Keyboard Cat, or Jeeves, and I will be sad to see them go.
How long before a "Hitler reacts to Hitler-reacts-to-videos being shut down" video is created? Internet, get on it!