I do not see how this proves anything other than what I have stated before. 9/11 happened because our government was ill prepared, arrogant and ignorant about the real threat. Nowhere on this page (which is from the highly reliable Wikipedia) does it state that anyone in our government had knowledge of the ATTACKS prior to 9/11. In fact, it just simply states that we MAY have known that there were suspected terrorists in our country at the time, which was probably commonplace then and is probably still so now. Again hearing this information AFTER the fact shines a different (possibly incorrect) light on it. Knowing what we know about Atta now, makes it seem impossible for him to not have been recognized for the evil he was planning and arrested or deported. But the truth is, in 2000 if he was on a list of suspected Al-Qaeda operatives in the US then he was just another name. Since no DIRECT mention of the date/time/method of the attacks were ever attributed to him he fell through the cracks. Just like so many other criminals do everyday in every country across the globe. He was not erased from memory to help cover the asses of the government who wanted to create a reason to invade the middle east.
This just feels like more conclusion jumping to me. The fact that a chart may or may not have existed with some dude's name on it doesn't make my mind leap to "the government MURDERED thousands of people as part of a massive global conspiracy."