At the very least he was indifferent to harming the US government. Despite the opinions of many commentors on HN this is not the same thing as defending the interests of US citizens (or indeed citizens of the world).
I agree with you that Snowden's actions was to reveal what the administration was doing and overreaching in its power. How do you protest our government's action without evidence, reputation, and without being dragged in the general media....it's not possible without looking like a conspiracy theorist.
This is why I respect Snowden. He gave up everything... safety, great pay, family... for what he believes in.