Ah, but I don't believe his actions have been consistent with this motive at all - and actions do speak louder than words. Since publicly revealing himself as the whistleblower, he's made a significant portion of the story about him and not about the issues he claims to care about - for much of the media and public, it's become just another human-interest saga with Snowden as the star.
If your sole motive is truly to inform the public about a cause, leak your leaks and then do whatever in hell you can to stay out of the way and not blow it. Perhaps he's just a glory hound, perhaps he really means what he says and didn't realize what effects his actions would have - but either way, Snowden did his cause a lot of damage when he put himself at the center of the story. We'd all be a lot better off if we'd never heard his name.