Possible use of explosives indicated by government's own briefs

A recent story about Tenet's new book by Robert Parry returned my attention to the contents of the August 6, 2001 Presidential Daily Brief (PDB). Parry seems to be arguing for criminal negligence, but he quotes the end of the August 6 PBD:

"The PDB ended by noting that “FBI information … indicates patterns of suspicious activity in this country consistent with preparations for hijackings or other types of attacks, including recent surveillance of federal buildings in New York. The FBI is conducting approximately 70 full field investigations throughout the US that it considers Bin Ladin-related. CIA and the FBI are investigating a call to our Embassy in the UAE in May saying that a group of Bin Ladin supporters was in the US planning attacks with explosives.”"

You may also recall President Bush's odd statement on September 15, 2006, when referring to the alleged details of KSM's interrogation:

"For example, Khalid Sheikh Mohammed described the design of planned attacks of buildings inside the U.S. and how operatives were directed to carry them out. That is valuable information for those of us who have the responsibility to protect the American people. He told us the operatives had been instructed to ensure that the explosives went off at a high – a point that was high enough to prevent people trapped above from escaping.”

One element of the PDB really happened: the hijackings. Why do those who support the official theory treat the additional possibility of explosives being used as preposterous?

Aside from the mass of evidence suggesting the use of explosives in the WTC, and other reports of exploding cars and mysterious vans in the vicinity, the evidence above suggests at least an operational awareness of the possible use of explosives in pending attacks, even in statements from people who do not personally support the CD hypothesis.