I'm glad you posted this because I am glad I read it. There is nothing revealed in it that would cause me to criticize Fellwock in any way. I admire him as he is described in this piece and I relate to and understand his feelings and thus his reasons for what he did.

One of Fellwock’s main targets in Vietnam was a particularly threatening North Vietnamese Army brigade. Using the NSA radio data, he helped prepare a map of the brigade’s travel patterns. That map guided an enormous B-52 bombing raid: One sortie per hour for 36 hours, lacing the area with 30 tons of explosives each time, according to Fellwock.

A few weeks later, he flew to the area and inspected first-hand the devastation he'd helped inflict. ... ... “I’d never seen so many bodies,” he said. It was a horrible sight and I knew I’d participated in it.

I do take issue with his current stand on Snowden's actions as posted in your introductory paragraph.

“I think Snowden is a patriot,” he said. “I admire Snowden and some of these other whistleblowers because they’ve come out in a time when there’s not a lot of political support.”

However, as someone who stayed in the United States after his own whistleblowing, he believes Snowden made a miscalculation by fleeing the country. “I think he should have stayed here and faced the consequences," he said. "I understand his fear, but I really think it was a mistake on his part.” [My emphasis]

Immediately before this is the statement that:

Today Fellwock doesn’t follow politics or the news. The last time he voted for president was in 1972, for George McGovern.

When I first called him, he had been only vaguely aware of Snowden’s disclosures. But as he read more, he said, he'd learned how little had changed since 1976. [Agai, my emphasis]

Not following the news might be an excuse for not knowing the treatment of recent whistle blowers including the financial ruin of some, the imprisonment of some, and the Presidentially condoned public torture of Bradley Manning that went on for months before he was convicted of anything. That is very different from Fellwock's situation and his probable evaluation of the risk of leaking as he must have seen it. 

Before publishing, Ramparts had consulted with the lawyer for Daniel Ellsberg, the leaker of the Pentagon Papers. Ellsberg's lawyer told them that the government wouldn’t risk exposing more secrets by publicly going after them for the article. He was right.

I note this because I very much disagree with the notion often put forth that a person committing and act of civil disobedience such as did Manning and Snowden are somehow demeaned and shown to be less credible, or their actions proven to be less defensible, by the fact that they did not voluntarily lay down on a cross after their "crime" so that the government could nail them. They knew the risk they were taking and they chose to take it for what I see as admirable reasons. That was their act of courage and it is not devalued, IMO, by their not volunteering to be a martyr to the cause. The obvious analogy in Manning's case is that a soldiers courage is demonstrated by his actions and judging his actions courageous does not require that they lead to his injury or death. 

 Just wanted to put this somewhere relating to snooping. I got it from a post by Corey Robin. It is a campaign poster from 1929.