Minh - I will respectfully disagree with you. When I bought this anemone it was deflated. In terms of the usual signs that we use to assess health, it was in deep trouble. I bought this anemone on purpose to help dispel the exact myth you are referring to.
I do not believe that feeding does more harm than good. I believe that feeding is exactly what they require to help get them through acclimation, especially when they are deflated or their mouth is gaping.
It has to do with my ideas about the spectrum of their health. In my mind, the inability to maintain appropriate tissue turgor (inflated vs. deflated) is very late in this spectrum and near death. If an animal is so depleted that it doesn't have the energy necessary to basically keep itself together, and you do nothing, it is very likely to die. If an animal is in this condition, and you feed it, it still may die, but it is not due to feeding it. It's because the animal was not salvageable. This is where there are anecdotal reports about how "feeding killed my anemone" and the myth that feeding harms them comes from.
My point is that for every H. magnifica that comes in, you can put it into three categories: robust vs. salvageable vs. unsalvageable. The unsalvageable ones will all go on to die despite any effort that you make. The robust ones are so incredibly healthy that in an appropriate set up you would have to try hard to kill them. The salvageable ones however, are on a continuum that slides towards one end or the other. It is these that you can save by feeding. If you feed one that is near unsalvageable, in my mind you can reverse the slide and take them towards the robust end. If you don't feed one that is sliding down, you can on the other hand, convert one that was salvageable to unsalvageable.
-B