I can't imagine going into an audition and being treated as unprofessionally as that. Sometimes even in a bad audition, you can hear a voice in there hiding, and a real vocalist would hear it too. I'm in no way saying that's enough to book a part, I'm just saying that you can be honest without being unprofessional.
But then that wouldn't make good tv. The Finnish version's Simon character is a racist (that's not just me saying that. Pretty much everyone I know thinks it too, just in case you think I'm being harsh). He tried the old Finnish trick of turning a foreigner down based on language - nevermind that 90% of applicants sing in freaking English, so what does it possibly matter? One of the judges herself, the Paula Abdul character, can often be found singing in bad Finnglish, so the critique just doesn't float. Then apparently, (I didn't see this episode) they had to take him at the next city's auditions because it was so bad they couldn't fill the quota.
It's just a crap show, where they treat people crappily and make crappy music. And people watch it because we're mean.
edit - to add fuel, and ratings to the fire, the judges answered some of their critics tonight by specifically making fun of the foreign dude only on the grounds of being foreign, and having a good laugh about it. Obvious ploy to get people to see what they'll do next, but sadly they weren't as interesting as our Little Britain dvd set. "Ehhh eh ehhhhh"