You are missing the important aspect of it, and that is, just like their citizens are fair game for us, we are also fair game for them.
I would be highly surprised if those agencies are _not_ allowed to "look" at our data, since they won't be breaking any "laws".
Fuck everything about finding loopholes and skating on the edge of what is legal. NSA has repeatedly lied so far, never apologied for it. A lie would come out and bam! exposed by Snowden's docs. It was spectacular to watch.
The bottom line is, I am more scared and afraid of our NSA than of the Chinese bogey men or "cyber warriors" out there. I have not seen anything but lies, trickery and dishonesty come out of their mouth. I think they are traitors and unpatriotic.
They are betraying fundamental principles this country is founded on. I can see how slimey mafia lawyers would want the laws re-interpreted to fit their clients' purposes ("well, it depends what 'is' is, your honor"), I don't want out government doing the same. It technically might be legal it doesn't mean it isn't shitty.