Why not? "Evolving Threats to Security"

We are continuing to examine the public's thoughts on naked scanners. This next section is titled "Evolving Threats to Security," and highlights both favorable and unfavorable reviews:

Commenters also addressed the evolving threats to aviation security discussed by TSA in the NPRM. Some commenters stated that TSA’s screening efforts are not linked to the decrease in aircraft-related terror attempts since September 11, 2001. For example, individual commenters and a non-profit organization stated that the threat attempts listed in the NPRM were thwarted by intelligence efforts, not TSA screening. Other individual commenters, however, supported TSA’s efforts to deploy tools like AIT scanners to detect and deter future attacks. Individual commenters credited secured cockpits and stricter policies for cockpit access with preventing terrorist attacks on commercial airlines since September 11, 2001. Furthermore, a few individual commenters suggested that in addition to enhanced cockpit security, passengers’ awareness and willingness to fight back deters terrorists from targeting planes. 

Several commenters discussed the evolving threat from nonmetallic explosives. A few individual commenters suggested that TSA’s response to the increased threat of nonmetallic explosives is not sustainable because terrorists will find other ways to hide devices. A few individual commenters disagreed with TSA’s focus on nonmetallic threats, because these types of weapons have been used for several decades.  

A few individual commenters suggested that the long lines at checkpoints, which the commenters stated are caused by TSA screening, are more attractive targets to terrorists than airplanes. Lastly, several individual commenters stated there is no evidence indicating that terrorist threats similar in magnitude to September 11, 2001, are increasing.