The point of this thread is they didn't send fighters up to escort it. They welcomed other countries doing so, but being outside office hours they were not inclined to scramble jets themselves.
I didn't say 9/11 was an existential threat. Knowing it would be used as an objection for my lack of encyclopedic completeness, I exempted it from the observation that most hijackings end peacefully. As for your "calculus", the only thing they can do is aggressively assure the hijackers don't turn it into a 9/11-style attack; shooting down a loaded airbus is not preferable to closing most airstrip options and letting lack of fuel force a landing where subsequent takeoff cannot happen.
The plane was already escorted by fighters from friendly nations. So long as the Swiss trust that the Italians and French are competent, why bother. That has little to do with 9/11.
Shooting down a loaded Airbus is definitely not preferable and the US has never done that. The right action is as you said to escort it to prevent a 9/11 type attack. In similar situations, the US has done precisely that. The US has escorted jets down.
I don't see how the actions of the Swiss is really all that different from anyone else. The current norm of escorting hijacked airlines with fighters seems appropriate. The only difference here is that the Swiss was willing to rely on the military of friendly nations to do it. It would be a whole other matter if the Swiss told the French to turn back and let the airliner land unescorted.
Are we talking past each other? Or maybe I'm not appreciating the differences you're trying to point out. I'm wary of any attributions to culture, etc. Most of what happened was fairly procedural.
I didn't say 9/11 was an existential threat. Knowing it would be used as an objection for my lack of encyclopedic completeness, I exempted it from the observation that most hijackings end peacefully. As for your "calculus", the only thing they can do is aggressively assure the hijackers don't turn it into a 9/11-style attack; shooting down a loaded airbus is not preferable to closing most airstrip options and letting lack of fuel force a landing where subsequent takeoff cannot happen.