Earlier quoted context omitted.
Snowden knows exactly what the consequences would be, because he's not the first whistleblower. Bradley Manning is still potentially facing the death penalty, and at the very least he will never see the outside of a jail again. And still plenty of people found enough reason to label him a coward. It is way too easy to be in a comfy chair and say that other people should throw their life away to stand by their princip…
Manning is not facing the death penalty, is not a "whistleblower" by any reasonable stretch of the term (except perhaps by lucky accident), and his actions were different from Snowden's, at Snowden's own admission.
As for not facing the death penalty, he looks like he's halfway at deaths door already, they're just taking their time about it. The world is watching the way Manning is treated and drawing its own conclusions from that.