You suggested that in order to be patriotic he should have stayed behind to face justice, administered by the same government whose "checks and balances" have so far failed to prevent the thing he's protesting. Why take his chances? Would you call a Chinese dissident unpatriotic for leaving China?
(perhaps I should have given a more specific translation rather than a literal one, you can read "trusting the government" instead of "loving". short Chinese phrases have a lot of leeway in meaning which is usually implied from the context)
I did not mean to suggest that he should stay behind to face the justice system which could be corrupt, I meant to say that he should stay behind and trust himself to the American populous, a lot of which considers him a hero.
When you are travelling around and running from something, things can happen. I've had a few friends die/be murdered while travelling in foreign countries so I have a personal reason to sort of understand when something happens or somebody dies while travelling. But at large in this country people have seen Taken or Hostel or some other anti-traveling movie that has conditioned them to think that travelling in inherently unsafe. By travelling you open yourself up to whoopsie-daisy style deaths in which it is just understood that you died because you were being incompetent in some fashion.
In the American legal system however, the jail which you are held in is responsible for your well being. And with somebody as high-profile as Ed Snowden, if something were to happen to him while he was in jail, everyone would know about it and some people would have to answer questions.
And if he were convicted of espionage while he was staying in this country, 1) His charges as a spy wouldn't make sense because it would be understood that he still considered himself a US citizen so he would have nobody to be accused to be spying for aside from the people of the US and 2) if he was convicted, imprisoned, executed or whatever could be the case, the laws and the legal system that did it would be under immense scrutiny by the ACLU, the EFF and anyone else the actions pissed off and would probably face extremely harsh repercussions.
Bradley Manning has been tortured and there has not been outrage on the level that would be enough to protect him. When Edward Snowden blew the whistle, he had no reason to think that he would have been more successful. Perhaps you would have done differently, but at this point I think it boils down to personal differences in evaluating a situation, so I wouldn't go as far to claim he is unpatriotic.