Propaganda worked on those people. I remember the news back then, it all focused on Snowden himself, rather than the revelations. Lots and lots of FUD in the opinion shows, all the talking heads were spending the bulk of their time opining on him, instead
Like the fact he left the us to escape prosecution, his landing in Russia. Remember they even tracked down his girlfriend or something ridiculous? I know I'm forgetting some of it. Anyway all that crap was designed to shift people's focus away from looking into his proof, and towards doubting the intentions of the person providing it. And boy, did it.
It worked, on a lot of people.
I still hear folks call him a traitor to this day, and they always parrot the FUD talking points i remember from back then to a T.