I don't think the issue is whether Kwan should skate GP, but that, unlike the past two years, where she turned down the invitations up front so that the next skater would be seeded, she left her name on the list until a few weeks before her two events. She did say that she would decide in the Fall, and she's not responsible for the way USFS advertises her presence, but, according to a bunch of posts I've read, her agent confirmed recently that she would be in GP, which sounded like a decision in the Fall, and now she's announced that she won't compete.
I, personally, don't think Kwan owes me any further explanation, but her (future) livelihood is based on how hundreds of thousands of people are willing to pay to see her headline shows, particularly when their kids idolize her. Popularity is at the discretion of the audience, and each member of the audience decides individually whether or not Kwan owes him/her anything and makes a future buying decision based on that. I suspect that there are more than a few heartbroken kids who got their parents to fork over big bucks for Skate America tickets, and they don't care that they'll see Susanna Poykio or Yukina Ota instead. Hard-core FS fans can believe that skating is bigger than Kwan, even if they are disappointed that she won't compete, but most general fans treat a local competition as an extension of a show, and the advertised performers are expected to show up unless laid up. General fans buy far more tickets (to shows) than we do.
Maybe this affects only a small number of general fans in the vicinity of the competition, and the rest of the public is blissfully unaware of a "controversy," or maybe it has an effect on her fan base. But if lack of exposure to actual CoP judging hurts her at Moscow, which is more generally publicized, I think her stock will go down with the general skating public, particularly if she does not regain the World title. (Ex: one Associate Press article that mentions this and gets repeated across the country. Husband reading the sports pages taunts his wife and daughter with, "Look at what your little ice princess did, lost the World Championships because she decided not to be prepared, and you think Figure Skating is a sport?")
I think Plushenko's situation, for example, is different: he will qualify for COI each year based on his Worlds placements, which takes care of his NA audience, but his primary fan base is in Europe and Russia. He's competiting in CoR -- which makes it seem like Kwan could have competed only in SA as the host country invitee -- and he's performing a number of shows to his natural audience.