This idea is mistaken because nobody knows what their intents are. Your idea of "just trust them" isn't comforting; quite the opposite.
A government that has lost accountability is far more dangerous than a terrorist organization. If you don't believe that, ask those who fled the Soviet Union, or who lived through Saddam's regime in Iraq.
The problem here is that there is no end to this. It will drag on and on, with more and more freedoms lost as long as people continue to cower in fear like this.
Frankly, I would argue that the 3,000 lives lost in the attacks pale in comparison to the total number of casualties that occurred during the Iraq War. You can look at the numbers yourself: http://en.wikipedia.org/wiki/Casualties_of_the_Iraq_War
Events like 9/11 have a significance beyond a raw casualty count, and you know that as well as I do. I'm not even sure what your point is. If you think OBL's goal was to inconvenience people at airports, you've left reality far, far behind.
Pearl Harbor was the first act of that war, not a cause of the war. Whereas Osama bin Laden didn't have much capacity to do anything beyond 9/11 style attacks, the Japanese were intending to take control of the entire pacific. There is a huge difference there.
For all it's doing wrong, the NSA has a goal in mind to try to protect the American people. If its methods become cancerous that is one thing, but factor in the intentions here. They are not trying to ruin lives, even though their perspectives might be warped.