The BBC and verbal slips

When George W. Bush made a verbal slip or John Redwood failed to know the words of the Welsh national anthem, the result was BBC headlines and years of jokey references on topical news quizzes. When Barack Obama fails to remember how many states there are in the United States, when Alan Johnson reveals he doesn't know what the rate of employers NIc is or when Ed Miliband is somewhat economical with the truth during a BBC interview... as little attention as possible.

Is there any reason other than bias that you can think of?