The government of a country, any country, owes allegiance to its citizens first and foremost. Our laws do not apply to people in other countries. I can't imagine that most large governments other than the US do run in exactly the same manner.

I'm not defending the NSA, but let's not be naive here. One function of the government is to protect its people from all threats, foreign and domestic. So yes, citizens of other countries are second class, and well they should be from some perspectives. Again though, there are lines, and some have been crossed.