I appreciate you're taking the view that it's a purely technical question, but moral questions are rarely far away from security concerns (why do you need the security?) and TFA acknowledges this by raising the moral issue directly:
Sometimes, the malicious insider isn’t so malicious. This is the argument many are making in Snowden’s situation these days
TFA doesn't resolve it directly, though. It goes on to liken Snowden to Terry Childs and then Childs to Jason Cornish.
This comes off as a weak attempt to tar Snowden with the moral dubiety surrounding Cornish's spiteful data deletion spree.
(More charitably, perhaps it's just a clumsy effort to indicate a subjective factor in such moral arguments, or perhaps the author is just rambling.)
At any rate, having mentioned the argument it doesn't answer it, apart from to say this point of view (the view that there are cases where people have pretty good moral reasons for breaching security) "isn't new."
The Slashdot story itself can be read as to imputing malice to Snowden (right at the end: "malicious insider") and indicating that the consequences of his leaks are "catastrophic" for the NSA. "Massively disruptive" would be a value-neutral way of putting it; whether or not it's catastrophic is going to depend on what views you have about the activities and goals of the NSA.
The technical question is an interesting one, sure, but don't expect people to ignore the moral dimension, especially when it's presented in such sloppy fashion.