How can you expect the controller to respond to the aircraft when he doesn't even know which aircraft made the distress call? The reason he didn't understand the call was probably because it was too rushed and non-standard. Even the people that had the time to listen over and over to the tapes to make the transcript for the video couldn't get it right!!!
This more than likely led the controller to believe it was a hoax. When the aircraft made its subsequent calls prefixed with MAYDAY the controller (although still suspicious) sent following traffic around and responded to the emergency.
Had the original call been standard and readable, allowing the controller to recognize the distress aircraft, the controller would have had no choice but to respond even if the thought it was a hoax.
here is another example where non-standard phraseology in the states caused confusion