What These 'Facts' Show . . .
"These facts show that the C-17 data was ex-filtrated directly from Boeing's computer systems."
Hmm . . .
I believe this shows nothing of the sort. Rather, it shows only that the files on the hacker's computer were arranged to make someone think they came from Boeing.
Alternatively, given the U.S. government's record of duplicity in the info it provides its' citizens, this may show that the government wants us to believe the hackers stole the data. Using past government practices as a guide, one could make a logical assumption that government planted the data, and that it's deliberately inaccurate, being used as a "honeypot".
When dealing with the U.S. government, or indeed any government, including the U.K and its' GCHQ who is partnered and in bed with the NSA, one must always start with the assumption that they are lying, and seek to prove they are not, rather than the other way around.