I hate to bring up something like Americal Idol (and its predecessor Pop Idol) in somewhere like Slashdot, but I think it's relevant.
In the UK Pop Idol, the judges were always honest - if they found someone who couldn't sing, they told them they couldn't sing. They told them to not give up the day job, to abandon their dream of being a pop star. On the flip side, if they were good, the judges said so - and because of that it really meant something.
In the few bits of American Idol I've seen, it's totally different. The judges (I seem to remember Paula Abdul and Randy Jackson in particular) when presented with someone who clearly didn't have a hope in hell of becoming a star of any kind, tied themselves in knots trying to say something positive. They just didn't ahve it in them to say "You're not a singer, forget about it". They'd say "You need to work hard to improve your rhythm" or " You're great but you're just not what we're looking for", and so on. Simon Cowell gave much more honest opinions and built a huge business out of doing it - but he was seen as Captain Negativity, the joke one, with the other two encouraging the no-hopers to keep their dream.
The result? People in the UK who got that negative feedback accept (sometimes reluctantly) that they won't ever be a star and go back to singing in the shower and leading a normal life. People in the US don't have that reality check, so keep on trying, making themselves look more and more ridiculous, desperate and above all untalented.