Was the failure to protect Americans on 9/11 the result of sexism?
I honestly don't know the answer. But I have this awful gnawing feeling in my gut that in some small way, it might have been a factor.
Let's hope I'm wrong.
To recap - an unidentified intelligence officer filed a complaint with the Department of Defense Inspector General for Intelligence alleging that the Joint Forces Intelligence Command withheld information from Congress during its investigation of intelligence failures on 9/11.
In his May 8, 2006, Formal Complaint to DoD Inspector General , the unidentified intelligence officer known only as IRON MAN wrote:
(U) Contrary to JFIC's formal report to the JCS staff, JFIC had a direct and assigned purview on international terrorism against the U.S., to include the operations of al-Qa'ida and the 9/11 attackers. JFIC was directly responsible to both Joint Forces Command (JFCOM) and its subordinate, Joint Task Force-Civil Support (JTF-CS) for all-source intelligence analysis of internationai terrorism against the U.S. To ensure the quality of such analysis, JFlC's commanding officer [redacted] established the Asymmetric Threat Branch (DO5), charged with reporting on asymmetric threats, especially terrorism. [redacted] was subsequently promoted to JFCOM J2. As a RADM and PACOM J2, she established another Asymmetric Threat branch at PACOM.)
It is my belief that the commanding officer described above is Rear Admiral (retired) Rosanne M. LeVitre, US Navy.
An online biography  details her background, opening with this sentence:
Rear Admiral Rosanne "Rose" LeVitre was the first woman intelligence specialist selected for flag rank in the United States Navy.
According to the biography, Rear Admiral LeVitre was also in the right places doing the right things with the right people at the right time.
After [Gulf War I], she was sent to the Joint Chiefs of Staff (JCS), Current Operations Directorate (J3). Among her duties was that of JCS representative to a National Security Council. She later served at two joint intelligence centers (JICs), one of which she commanded. After her command tour, she became the Director for Intelligence (J2), U.S. Joint Forces Command, Norfolk, VA.
On selection to flag rank, Rear Admiral (ret) LeVitre assumed the position as Director for Intelligence (J2), U.S. Pacific Command, Honolulu, Hawaii. From 2000 to late 2003, she oversaw intelligence operations at a time of increased tensions, from the EP-3 aircraft incident with China, to the Global War on Terrorism, and crises involving India-Pakistan and Korea. She conceived of and oversaw implementation of an expanded information sharing architecture, involving traditional allied partners, non-traditional alliances and non-DOD entities to include the FBI, state and local authorities.
Please re-read that last sentence again.
She conceived of and oversaw implementation of an expanded information sharing architecture, involving traditional allied partners, non-traditional alliances and non-DOD entities to include the FBI, state and local authorities.
Of the Asymmetric Threat Division (DO5), the Defense Inspector General for Intelligence wrote this:
In 1999, the Joint Forces Intelligence Command created the Asymmetric Threat Division to take a non-traditional approach to analysis. The Asymmetric Threat Division provided current intelligence briefings and produced the Worldwide Terrorist Threat Summary in support of the Intelligence Director for the United States Joint Forces Command. The Asymmetric Threat Division also provided support to the Joint Task Force-Civil Support. The Joint Task Force-Civil Support assisted civil authorities with disaster assistance. 
IRON MAN pretty much alludes to the fact that DO5 was ahead of its time:
(U) The Asymmetric Threat Branch in JFIC was a forerunner of current all-source fusion centers. Unlike other analytical offices in the intelligence cornmunity, DO5 members had
a wide mix of skilis in all six intelligence disciplines - HUMINT, OSINT, COMINT, ELINT, IMINT, and MASINT. Consequently, DO5 was able to develop and use all-source, original analysis in a manner probably then unprecedented within the intelligence community. 
The Asymmetric Threat Division was Rear Admiral LeVitre's baby, making her truly a visionary in the intelligence community. But according to IRON MAN, LeVitre's replacement shut down DO5.
(U) [redacted] the last JFIC commanding officer under which I served, was adamantly opposed to JFIC conducting any original analysis of al-Qa'ida, and directed such work be stopped in late 2000-early 2001. 
And that action - actively shutting down DO5 - puts a very different spin on things.
Someone please tell me that DO5 wasn't shut down because of sexism and that as a direct result, 2,753 people died on 9/11 because the boys club didn't take girls.
Because if that's the case, that's some seriously [redacted] up [redacted].
 Attachment - Unclassified FOIA Response PDF
April 8, 2011
Formal Complaint to DoD Inspector General
re: JFIC and Congressional Inquiry
May 8, 2006
 See: Members » Rear Admiral Rosanne M. LeVitre
The Consensus for American Security
 Review of Joint Forces Intelligence Command Response to 9/11 Commission PDF
Deputy Inspector General for Intelligence
United States Department of Defense
September 23, 2008
Declassified March 5, 2010
From the Federation of American Scientists
Report: Intelligence Unit Told Before 9/11 to Stop Tracking Bin Laden
By Jeffrey Kaye, Truthout, May 23, 2011
Abbreviations - used above
COMINT - Communications Intelligence
DO5 - Asymmetric Threat Division
DOD - Department of Defense
ELINT - Electronic Intelligence
FBI - Federal Bureau of Investigation
IMINT- Imagery Intelligence
J2 - Director for Intelligence
JCS - Joint Chiefs of Staff
JFCOM - Joint Forces Command
JFIC - Joint Forces Intelligence Command
JIC - Joint Intelligence Center
JTF-CS - Joint Task Force- Civil Support
MASINT- Measurement and Signature Intelligence
OSINT- Open Source Intelligence
PACOM - Pacific Command
RADM - Rear Admiral
US - United States of America
USN - United States Navy