Exactly this. Lockheed tells its employees to be very careful about discussing the F-35 in public, lest information be inadvertently disclosed. Obtaining and maintaining a security clearance is a condition of employment in the defense world, so those who know and could clear up many of the disagreements cannot really say much. Even disclosing that you work on the program is not encouraged.

People with knowledge about airplane design, air force procurement, the personalities and politics involved, etc. could contribute quite a bit. They don't need to be Lockheed employees or to divulge top secret or proprietary information.