First, I think the argument should be kind of split up. If you use Auto-Tune for its intended purpose, it's transparent and you can't hear it. It just corrects the pitch of the notes so that the vocals are perfect. That's where the argument about people using it as surrogate talent comes from. If it's being used during live performances say, then I understand that argument. For studio-recorded songs, though, what's wrong with a tool that makes it so the vocals are perfect the first time around? Is it really that much more "genuine" or "talented" of a musician to spend hours and hours redoing a track, or going into the tape and punching in bits they screwed up the first time? Or how about just swapping in other musicians to play the parts? Like on "Love Me Do," they didn't like Ringo's drumming, so they got somebody else to do it. That sort of thing's not at all uncommon in pop music, and you notice it just as much., listening to the song.

As for the robot voice thing, that's an effect. It's not being used because the singer can't sing (Though even when Auto-Tune is used to correct pitches, it's generally not because the singer couldn't hit them, it's so the singer can hit them in one take, without using up lots and lots of expensive studio time redoing it.), it's being used so that the vocals will sound a certain way. You might not like that effect, but unless you only listen to acoustic music, complaining that people use an effect on a song is kind of silly. An electric guitar with distortion on is just as much an effect as using Auto-Tune to make a robot voice.