If you want to make a case for an "ethical system" in which mass surveillance is good for humanity be my guest (and PM me your email login credentials while you're at it: I promise not to use them irresponsibly).
The NSA is made up on individuals like you or me and Edward Snowden has made the case that there's little preventing any insider from accessing what they want on whomever they want. As the surveillance state becomes an accepted part of modern society there will be those who seek involvement in it expressly for the purpose of abusing or exploiting their power.
They are individuals, yes (though they are certainly not random people), but they still operate within a structure that shapes their actions. For example, while I oppose it on philosophical grounds, I don't see an NSA operator exploiting my email credential for any personal purpose. But some random guy on HN - who knows? He might just post them on 4chan for the lulz.
It's simply a facile argument that weakens the real arguments against mass state surveillance.
It's not a bad argument, there's just better ones.
For example, while I oppose it on philosophical grounds, I don't see an NSA operator exploiting my email credential for any personal purpose.
It's perfectly possible to be crushed by a system without any of those operating the levers knowing or feeling anything personally about you. Systemic exploitation, a corrupt system if you will, is hardly better than corrupt individuals within a system, and the most horrific things in history all were rather apersonal, that's kinda what allowed them to reach an otherwise impossible scale, ferocity and longevity.
People distrusting people while trusting faceless agencies is the problem, not the solution.