1: Greenwald is an American so the actions of the US government are relevant to him and his readers.
2: Greenwald is a lawyer, trained in US law, therefore the actions of the US Government vis-a-vis US Law is a suitable topic for him to cover.
3. China and Russia have been oppressing their people and their peoples rights for a long time. Neither have a constitution that is supposed to enshrine the rights of the citizens. SO there isnt much of a story there i.e. russians have no constitutional right to privacy, when that privacy is invaded by the state because the state has enacted laws that allow it to do that, there is no story. Plus even if there were there are probably russina lawyers and journal;ists who would be more knowledgeable on the subject and could bring it to the awareness of their russian readers. I doubt many russian media watchers read a lot of greenwald.
4. The US sells itself as the land of the free, so their hypocrisy makes the story worthwhile/interesting. China and Russia have never really hidden the fact that they will spy on anyone and everyone that they can. US says "we are your friends" and then spies on everyone regardless of their status as friend or foe.
But you know handy to throw in a straw man argument to try and deflect attention away from the US government and make the journalist the bad guy in this situation.
Counterpoint: If something goes without saying for long enough, people stop knowing it, because they never hear it.
The "drunk looking for his keys under the streetlamp" model of news reporting is indefensible. Let it go long enough and you end up with a large population of belligerently uninformed people, like we have now, who think the United States is the most violent, oppressive, and brutal government in the world, and that Americans have no human rights. This has real world consequences of an increase in relative political power and legitimacy for genuinely oppressive states.
Really?
https://en.wikisource.org/wiki/Constitution_of_the_People's_...
https://en.wikisource.org/wiki/Constitution_of_Russia#CHAPTE...
I find it an interesting puzzle that the U.S. constitution is so well-respected that people routinely win court cases (and invalidate legislation) by asserting rights under it, while in China apparently the idea that the constitution should substantively constrain the government is considered naive and harmful.
https://en.wikipedia.org/wiki/Weiquan_movement#Retrenchment_...
In the past two weeks:
https://theintercept.com/2016/02/19/for-russia-censors-only-...
https://theintercept.com/2016/02/17/the-horror-story-of-publ...
https://theintercept.com/2016/02/15/putin-doesnt-need-to-cen...
https://theintercept.com/2016/02/24/bahrain-finds-opposition...
https://theintercept.com/2016/02/23/egypt-bars-journalist-fr...
Obviously there's more if you look further back. They did a whole documentary series on the Greek austerity deal, for example.