Secondly, that IFF is used by EVERY air traffic facility in the world, not just military. The aircraft transponder is the airborne component of the 'IFF' system.
My theory? well, in addition to being a controller, I also ran an aviation consulting business for 25 years. I have read/studied literally thousands of accident reports, and been involved in a few investigations. There has been so much conflicting, erroneous, retracted and redacted, mis-reported, mis-analyzed, unattributed information that only a fool would say he had a good idea of what happened. And I ain't that fool. What a damned goat-rope.
Again, read my post, I never used the word “Identity”. I said “Identify” Friend or Foe which is the Marine Corps challenge to unknowns. I suffer from my training also.
Of course there is an unfortunate haze of factoids that are sinking or swimming.
Perhaps I am foolish enough to look through and beyond them and try to include the possible religious/political strategic hints that may be driving the tactical aspect of this mystery.
I think my theory is wandering from the possible to the probable and would appreciate anyone’s take.