I beg your pardon.
You wrote: “And what evidence is there that all of this is anything other than coincidence? The whole story seems contrived.” Not I.
I do not believe in coincidence despite being open minded about most things. Meaningful or meaningless coincidence.
I wasn’t trying to defend or offend Jung.
Back to my probably correct guess: The Communist Chinese abducted them and tortured them (and used mind drugs and paralytics on them) to extract important scientific secrets to use against America.