Idol curiousity...

I have a question... why on American Idol when a person is told they've been voted out by America, why do they then have that losing person SING again? And worse yet, the same song! And they're on the verge of tears, can barely talk because they're upset, voice quivering, and yet they're expected to sing? It's like they're being told "America thinks you suck, but here... show them just how bad you really are!" I just think it's kinda mean. Simon must have a "torture America" vendetta.