I'm no engineer, but it sure doesn't sound right to me, either. A well lined hard case which embraces the guitar tightly enough to prevent its moving ought to be able to protect a guitar against moderate impacts. I would think that the lining would help to reduce the transference of impact shock.

On the other hand, I can see how a thickly padded gig bag could accomplish the same thing to some degree.

The difference, in my opinion, is that the soft bag allows virtually no protection at all from crushing.

And now, as a friend of mine is fond of saying, I have told you more than I know.(*G*)