Have we been blinded?

As I sit here after watching that clip, i can barely contain all the thoughts that are running through my head. I think me, just like everyone else out there saw the attack on 9/11 for what it literally was: a horrible attack on the World Trade Center. We tuned into the news and we saw the horrible images of the planes crashing into the buildings, we saw the ashes consume the city and we saw the weeping faces of those who lost loved ones. But over all this we saw countless speeches from our president, letting the nation know that he was going to do everything it took to find those responsible. Basically, what we saw was what we were given to see. I for one never bothered to take a deeper look into things.
The god-honest truth is that this clip has left me speechless because it makes a very good point. All of the compelling evidence in those clips points to the possibility that the we might have been behind our own attack! Why wasn't the nation put on high alert when all those other countries warned the US about possible ominous threats? If asked that question what would the answer be?
The clip also shows an extensive amount of eye witnesses who heard bomb related explosions going off inside the building right before the building collapsed. Why wasn't this further investigated? If the buildings were getting crashed overhead then why the hell were bombs going off inside? Though it isn't proven, the amount of people claiming to have heard the same thing isn't just a coincidence.
But you see, all of this has just simply led me to ask the simple question: why? Why would the US do this to itself? What would the reasoning behind it be? What did they gain from killing millions of people an leaving our nation in debt. I'll wait patiently for the answer...