Remember, the TSA staff is committed to making the airways safe from the bad guys... but they aren't geniuses. Go look at the TSA employment site and you'll see that the requirements for becoming a screener are not terribly challenging. The pay, too, is commensurately modest. Screeners are GS 5 to 9 positions.
The screening supervisors are expected to be more knowledgable, but they are the low end of "mid-grade" civil service - GS 11. I don't think we can expect too much from them, especially any specific knowledge about film, etc.
TSA screening personnel don't seem to know much more than what (little) they've been told in tehir training; same seems true for the supervisors They certainly aren't willing to "take our word" on what they could/should be doing WRT film inspection.
Arguing with TSA, or even trying to have an intelligent conversation, is often fruitless. They don't seem to have in-depth knowledge of film, fogging, or other potential x-ray damage. They don't seem to be empowered to alter inspection procedures that they are taught (whether those procedures are right or wrong). They aren't empowered to inform us (the fliers) with rationale for any of the procedures... in fact, they would probably claim that it potentially reduces their security posture to tell us why they do what they do.
(I asked once why they make us take of shoes one day, but not the next... they told me that they couldn't discuss the details of their procedures but I didn't have to take off my shoes at all... they can, alternatively, subject me to the "detailed security screening". Fearing a strip search by a big, burly, wild-eyed TSA screener who, incidently, kept snapping his rubber gloves and sporting a weird grin while telling me this... I put all of my film on the x-ray belt and almost offered to let them blast it twice.)
I must say, however, that there is quite a bit of evidence available on the web indicating that the x-ray/CT machine manufactures, such as Rapiscan and Invision, have participated in, both, internal R&D and industry studies to understand the magnitude ofthe problem, *try* minimizing the effects of this screening technology... or provide fair warning.
Me personally... I ask for hand inspection every time I fly (and it's been WAY too often over the past few years)... but quickly volunteer to put my film through the X-ray machine at the first hint of a screener desiring to open a LF film box or the foil wrappers of MF film. I've never seen evidence of any damage... but maybe my day has not yet come.
[disclaimer... I'm not defending any moronic behavior of TSA screeners or their supervisors. I've had good,and questionable, experiences with TSA screening and try to keep an open mind. The qualification/salary information I mentioned above comes from the TSA web site and I haven't verified accuracy.]
