I think Snowden's 'crime' was unfortunately necessary because there was no other way to call attention to the government's Constitutional abuses, past, present and future. But here's the problem with civil-rights era analogies: Rosa Parks, MLK Jr., and other prominent dissidents stuck around and took the heat. They spent time in jails that probably made Guantanamo look like Club Med by comparison. They were attacked by police dogs, sprayed with fire hoses, and were generally treated like shit. In many cases they watched their friends and compatriots die violently.
What they did not do was haul ass to Hong Kong.
Now, I can see why Snowden did that, and I certainly would have done it, myself. Why stick around for the disproportionate punishment that would follow an Espionage Act indictment? Snowden has no reason to believe he would even be given a trial, much less a fair one. He is no different from Anwar Al-Awlaki in this administration's eyes, being a US citizen who (we're told) stepped a little too far out of line for the judicial system to handle. Snowden just has a whiter sounding name, that's all. I don't expect him to martyr himself.
Nevertheless, the fact remains that he did flee to the far ends of the Earth, which isn't a valid act of civil disobedience as we know it from earlier eras. Right or wrong, he can never get that lost moral authority back. So it's best not to defend him by comparing him to Civil Rights figures who faced the consequences of their illegal acts.