How old are you? I think a lot of younger folks don't fully adjust for important factors: plane hijackings used to be much more common, 9/11 was committed by the second group of Islamic terrorists who tried to blow up the World Trade Center, and 9/11 was the third major terrorist attack by Al-Qaeda in a 4 year span. It's easy now to say that it was a crazy worst-case scenario, but that was not at all obvious then; for all we knew, securing cockpits might have been impractical, and we'd just have to prepare the Air Force to shoot down a couple hijacked flights every decade.

There were real excesses, and I ultimately agree with you that many of them were predictable in advance, but there was no feasible version of a response that did not go at least a little into crazyland. It was a crazy time.