While I agree that Rosie has no redeeming qualities whatsoever, I have to disagree totally with your characterization of Simon... In the very few episodes I’ve seen he’s been completely honest, if blunt. The performers could sound like someone throwing live kittens into a wood chipper and the other two judges would smile and say “Oh, that was lovely!”
As far as the eye rolling goes, I didn’t see the episode in question but if the performer was attempting to exploit the tragedy to get more votes they deserved a great deal worse than an eye roll.
Simon is a huckster. He’s supposed to be looking for talent. Any honest talent scout is going to have a screening process. He should be screening out these twerps who can’t sing, and weed them out before they even make it in front of a television.
But he doesn’t, does he? That’s what makes him a huckster and a phony.
Furthermore, he really does not know a lot about the voice. He knows more about what sells in popular music. Good for him. But he often passes off his vocal criticism as if he actually knows what he’s talking about. He clearly doesn’t.
Or "Yo, Dog!"