And as much as a lot of us here (myself included) think they're a net negative on the world, that doesn't mean they don't come with positives. They may not catch all threats but it's highly doubtful they catch none.

I'd wager that if you broke it down to the core elements, people aren't against the NSA but against the techniques they use: lack of transparency, gag orders, mass surveillance, etc.

And just to give you an actual third separate argument, the NSA existing keeps security in check. The threat of an entity that turns theoretical attacks into actual attacks means you can't get away with the "it'll never happen" excuse when building a secure system.