That quote is from "Notes on the Next War: A Serious Topical Letter" which was published in Esquire in 1935 and was about war (based on his experience from WWI), not about surveillance or about standing up for democracy in times of peace.
FBI opened their file on Hemingway in 1942: https://vault.fbi.gov/ernest-miller-hemingway
Nobody in the US will "die like a dog" for supporting a presidential pardon of Snowden and Hemingway did not suggest that one should stay out of politics.
"They wrote in the old days that it is sweet and fitting to die for one's country. But in modern war, there is nothing sweet nor fitting in your dying. You will die like a dog for no good reason."
-Earnest Hemingway