I don't think anyone is arguing about the cause and effect. But the point is that a tin aeroplane, having been bent at its most bendy bit, can subsequently be unbent/unbuggered, albeit very expensively, as in the case of those two 767s.
But a 787, on the other hand, subject to the same forces, clearly isn't going to just crinkle prettily - and if we're not talking about replacing frames, stringers and skin panels, what are the implications ?