This is terrible. When will people learn to NOT use computers at all for some things. Use typewriters and spend a little bit more on administrative workers. You trade in processing efficiency for making these catastrophic breaches rarer.
To put it into perspective Manning only got the data out because they were lax about securing the CD-burner in the computer he was using.
But what's the alternative? Even if you air gap things very, very aggressively you still get owned. The CIA has said that air gaps have never stopped them. Ok, so what are we going to do? Getting data out from computer systems is too easy. Things should be pen and paper and maybe specialized typewriters (there are ways of bugging typewriters or using sound recordings of the typing to reconstruct sentences).
At the very least we should keep our foreign agents out of our databases.