I agree, it is not a scenario that is ever likely to have remotely registered in the design process, and I also agree that to call it a design flaw is inappropriate (that suggests the aircraft is not 'fit for purpose'). It was unfortunate that such language was used.
There are many design studies into the effect of all sorts of threats (OK military funded design studies) which I suspect would surprise lots of people who have never worked in such an environment. As such, I can to some extent understand the reactions.
Consider:
1. Not all the information that is required to answer the question posed is inacessible.
2. The lifecycle of a class of planes is suficently long that projecting requirements several years into the future is not unreasonable.
I personally would like to see more "visionary" or "conceptual" discussions, some of which will be ridiculed but nevertheless enjoyed. For example, discussion of alternative flight propulsion in the light of environmental concerns and hydrocarbon fuel depletion is a subject that will become of releveance in the long term, yet it would be pointless to refuse to debate it just because it was not a current commercial decision factor.
I strongly believe that true professionals never ridicule those who ask questions, despite how silly they may seem.