OK, back to your original question:
Excuse the nature of this contentious thread but I would like some watertight reasons for why the current legislation even stands…..
Please enlighten us as to what legislation you are refering? We have merely speculated as to the rationale; maybe you can put more meat on the bone.
PS. I, like many, see no link between your question and the "safe(ty) of air travel". If you mean "security" then I think you have had a reasonable response. Just becuase the gold old USA does something, doesn't mean that we have to automatically jump into bed with them.
PPS. Why am I allowing myself to waste any of my time on such drivvle?