If the public interest and the principles of freedom were served by the leak, then that should be treated very different than a purely self-serving (or dangerous) leak.
Even the Uniform Code of Military Justice makes it clear that soldiers have a duty to not obey an unlawful order. The idea is that we are all answerable to the principles in the constitution (and, if you believe, to a higher power or to the idea that some rights are considered inalienable).
So, no, I don't agree with your implicit assertion that all of this is arbitrary and depends only on the whims of the individual.
Snowden didn't just blow the whistle on some shady activities, he dumped hundreds of confidential documents that put at risk the lives of hundreds of operatives working for your freedom and others'.
So: Why did you use the word "dumped" and can you explain explicitly what he did wrong?
So, like Manning, he definitely leaked stuff he didn't need to leak that harmed NSA's foreign operations that Americans were OK with. The kind the NSA was created for. That's not whistleblowing like his domestic stuff that Alexander and Clapper lied about. That makes him a whistleblower on domestic leaks and traitor on most, foreign ones. I put in for pardon given benefit of the whistleblowing but he's certainly guilty of damaging leaks.
I just don't see a reason to charge him if lots of scumbags on top are still walking free despite clear potential for Contempt of Congress or perjury charges. A little unjust, yeah?