Again, did the anthrax terrorism that paralyzed the nation's capital arrive on a Washington DC dock, or via the US Postal Service?
I may be idiotic, but at least I'm aware of world events over the past five years. More than I can say for you.
Go back to sleep, or watching cartoons.
And, once again, prior to 9-11, did hijackers take planes with the intent of using them as guided missiles against targets, other than in Tom Clancy novels?
You don't just defend against the last attack. You have to work long and hard to prepare for the next one using new techniques. Putting a weapon on a ship docking at a port puts it right next to a large American city.