Well -- Americans may have a lot of media to choose from, but 95% and the most accessible media is giving the "mainstream", gov't supported line.
The majority of people will eventually fall for it.
So although they may have initially been shocked at the relevations, the campaign immediately started to:
1) Justify the NSA spying "It's protection against evil terrrorists who HATE FREEDOM and the American way of life... and pedophiles, do you support them....?"
2) Focus on the person of Edward Snowden, rather than the issue: I.e. "He abandoned his girlfriend who is good-looking and a dancer!" "He said XYZ in an IT forum 5 years ago", "He is just after the attention", "He's got mental health issues"..... I.e. blackpainting and general distraction from the actual topic.
3) Insinuating that "Putin is involved", "Russia is playing games and needs to be taught a lesson..." and generally using their ex arch enemy's completely incidental involvement as a distraction from the real topic.
So after a month of this, most people are duly distracted by the above point, concerned about appearing un-patriotic...
It's also very easy to hoodwink non-technical people on this technical topic. Making it sound less serious that it actually is.
The actual technology behind it, and the potential implication of this amount of spying is simply not within most people's grasp, from a technical perspective.
That's why this is so HUGE in the IT world where I work. Most people DO understand how truly sinister it is, and the absolutely mind-blowing implications. But for non-technical people it's understandable that it is hard to actually understand the problem.
They are building huge data centres inside mountains for this, for goodness sake. The scope is incomprehensible. They want ALL data, from EVERYONE.
It's a combination of the worst spying thriller and the most spooky dystopian sci-fi you can imagine.
Right now they can't decrypt and cross reference everything. But give it a few years, and they'll be able to use this data to pull out a full profile on anyone. Everything from their shopping habits, social life to political views.... Stasi (to mention this classic example of a spying org) couldn't have dreamt of this and they might actually have had ethical reservations about it... But not so in the USA!
Propaganda at its best, using "free" press... Most people don't see it happening.
Snowden did Americans a big, big favour at a huge price to himself, but sadly most Americans (just as he fears) are not in a position to appreciate it. Only somebody who seeks out alternative news sources and has the technical background to follow it, will be able to see the full picture.