Back in the day, i.e. when I watched television, it was the audition episodes that sucked me in, and then after, when they're in Hollywood for the rest of the season, I'd quickly lose interest – my favourites always got cut early on.
With regards to the truly terrible singers, all of those thousands of hopefuls go through preliminary auditions before they get anywhere near the cameras. Those first rounds of judging are to filter out the unremarkable wannabes––they're just plain boring. The ones that make it before the cameras were all chosen as the stand outs; some were selected for their exceptional musical talent or charisma, and the others were picked for their superlative musical mediocrity or some tragic aspect of their personality, given false hope with insincere praise and advancement to the next round of auditions, and then, finally, they are brought before the cameras and fed to the lions so that millions will laugh at them when the tears of humiliation stream down their cheeks.
Perhaps it's the viewers that are out of touch with realty, not the doers.