I do think that things he's said and things he's done actually undermine his stated cause. He started out by portraying himself as a conscience-driven individual who wants to expose what he believes are gross violations of civil liberties without becoming a focal point of the story.
He's now made himself the center of the story, has expanded his motivation to moral outrage at all forms of spying, etc. Add to this the various inaccuracies, melodramatic over-statements, tangents into matters entirely unrelated to civil liberties, and really, just the act of flight to begin with.
It seems to me that much of the time he does or says something he's moving perception away from somewhere on the the 'mildly ambivalent moral actor' end of the spectrum where he started and towards 'clueless opportunist'.
That's a terrible thing because, and I agree with you, a number of the things he says are not just extremely plausible but important matters of civic discourse.
I'm not sure how you would expect him to conduct this disclosure without the "act of flight" or "becoming a focal point of the story".
Or, say, here's a take by Slate's resident libertarian: http://www.slate.com/blogs/weigel/2013/06/17/snowden_veers_i...
When your natural support constituency starts saying things like that you have a serious (and, inexplicably, self-created) image problem. I believe this is an actual thing rather than, you know, you and me just shooting the shit on a nerd message board.
I guess the simplest way I can put it is - I wish he'd stop taking his cues from journalists, however high-minded and well-intentioned and start working with a local lawyer specializing in human rights and civil liberties issues, yesterday.
The substance of his claims is extremely plausible and consistent with facts that have been long known.