Exactly. My wife and I were discussing that. I'm sure the judges are just sick to death of people who clearly have no singing ability whatsoever wasting the judges' time. I'd probably start to get a little nasty too.
I also think those that are responsible for the pre-judging - the screeners who decide who should go through to Simon/Paula/Randy and who shouldn't - are purposely sending through really bad people, knowing that Simon will be fired up. It makes for good television.