If I don't approve of the next war, do I need to write a letter to the president before I have a moral license to engage in civil disobedience? No, clearly not.
There are lots of ways to question authority, some are meaningful and others are an utter waste of time. I would encourage you spend what little time you have as effectively as you can.
My point in the comment above was that it shouldn't be seen as damning that Snowden didn't bring up his objections through "official channels" since no reasonable person can be expected to believe that that would have been anything other than a waste of everyone's time.
This wasn't a single mission or policy made anywhere near Snowden in the chain of command. We're talking about a fundamental element of the mission of the entire organization. There are certain policies and actions that it would have make sense to complain about, for instance an overzealous supervisor making specific demands that seemed to contravene express policies or traditional behavior. Not this. Not official policy that had been expressly sanctioned by the highest level of authority in the organization. It is insulting to tell us that official channels existed for addressing this kind of complaint.