We know this explicitly?
Again, do we know this? I'm seriously asking, as this thread is huge and I haven't followed everything.
If the point is simply that it's 'out of date software' (assuming this is even known), all I can say is I used to work at one of the big 3 defense contractors. You'd cry if you know what we were running. Still haven't moved past XP for client machines ... IE6 didn't go away all that long ago ... many of the server OS's are 'out of date'.
Shit, you should see what the gov uses. Many times though, this is actually on purpose. There's a difference between jumping to the newest and the best, and actually maintaining security. The reality is it's a devil you know sort of game. Jumping to the newest typically means new unknown security flaws. Large-scale systems and big companies with important data purposely wait a while until a lot of the issues have been rung out and patched.
Now if there is verifiable evidence that they were not patching known flaws that have released updates ... that's a very different argument and would certainly make accusations of negligence more realistic. If however they were keeping those sorts of things up-to-date, then it's likely they were keeping their system more protected, not less.