I don't get it as well. I know it's paradoxal, but I'd understand a comeback if she was 4th or out of the podium of the last Olympics. But she was silver, and she was even quite lucky to get it instead of Slutskaya (I'm not bashing her, I love her as an artist!). If she hadn't that silver, them a comeback could have more sense to my eyes.
But above silver there is only gold and I'm sure she is aware of what it takes to beat Kim (read: some 3axels).
Maybe it's because I don't believe in comebacks in general. I think Plushenko's has more sense because of two reasons: first, when he was in shape he was (almost) unbeatable for a long time, so assuming that he can possibly come back in shape he'd be actually able to win some event. Secondly, Russia's men field is so depressing that event placing in the top 10 would save Russia from a real shame.
I believe the American girls right now are adorable and they can do a good competition in Vancouver. With some luck Rachel could even be a medal contender. So please let this girls gain some experience. They will grow up very well. It just take time and patience sometimes

Instead, u.s. dance couples and men look as good as ever