I had the exact opposite reaction to Snowden's revelations about the NSA that everyone else did. Prior to that, I had thought it is a ridiculous infringement on people's privacy. I thought it was terrible what the NSA was doing. I advocated heavily for anyone thinking about heading in that direction to rethink their life, and work on something constructive.

Snowden revealed so much more data collection than anyone could have imagined was going on. People's thoughts as they were evolving, the NSA could watch someone and know what they were doing before they did! But compared to this level of surveillance, which was WAAAAAY beyond anything the Stasi or Gestapo ever did. And did people think that they were living under a police state? Did people have to watch what they said and wrote? No.

Because the NSA treated that data with an incredible amount of responsibility. They were, quite literally, a black box:
https://www.google.com/search?q=nsa+building

And you were hard-pressed to find irresponsibility there. They actively denied their capabilities, hid from the public, remained completely hidden. This is great: it's the opposite of living under a dictatorship. It's great that they hid so well. I gained enormous respect for them. In addition, I thought that that data would have the most amazing historical significance of anything humanity has ever recorded.

One of the greatest insights into the past that we have is at Pompeii, where Vesuvius erupted and covered a city in ash, freezing everything just as it was, in the middle of conversations. Blackboards were filled with crude insults to the teacher. People left graffiti everywhere. It gave us an incredible amount of information.

Can you imagine in the year 3,000, when the NSA's documents are ancient history, what kind of insight into the human condition, machinations, good guys, bad guys, plans, history, humanity can gain by seeing every single person's complete activity down to the second, down to when they were composing their thoughts?

I believe that history can be a huge lesson, and not only "those who do not learn from history are doomed to report it", but that it's better to learn from somebody else's mistakes. In the year three thousand, humanity can learn so much from a complete black-box recording of everything that has ever happened today.

Compared to this level of access - which is illegal, which they denied, which they still do not acknowledge - about the only abuses someone can name is that a general had a sexual affair (which most people would consider immoral) and they manufactured a back story for how they learned this. That's the worst thing I've ever heard about them.

Why do they have to exist at all?

Some people suck. A free society means people are free to do and think whatever they want. Some of them will choose to pursue great ideas and ideals, set up huge disruptive businesses where they generate billions of dollars in true value for society, that never existed before. The easiest way to be a millionaire is to make something great, and let people buy it.

Other people will look at a millionaire, and make an elaborate scheme to blackmail and extort them. They think that the easiest way to make money is through theft, scamming, blackmail, extortion. What should happen if Larry Ellison's wife is kidnapped? What if a virus writer encrypts your files and illegally blackmails you to decrypt them?

In the latter case, the person should be brought to justice. And this should happen: https://noransom.kaspersky.com/

Everybody knows what happens under an anarchy, or a complete lack of rule of law: people spend their energies arming up personally, as opposed to building relationships, products, ideas, or being productive. People don't trust each other. Might makes right.

How much better than that is the fact that if you concoct an elaborate kidnapping or terrorist plan, the appropriate agency can get the black box to spit some facts out about this?

Since learning the extent of the information the NSA has siphoned up, and the incredible responsibility that they've treated this with, I would not have a problem if they had a a multi-petabyte database with every thought, action, keystroke, of everyone on the planet. If anything it is too bad humanity is not quite in a position to be united into a single world government that this is a part of.

I support the NSA in siphoning off all the data, treating it responsibly, hiding, cowering from oversight, denying what they are doing (even from other agencies), withholding data, and being the black box that they are. I don't mind if readers here work for them.

This is just about the opposite of what I thought about the NSA before the Snowden revelations!

Their very existence keeps people honest. When people online happen to be talking about how to do something destructive, they joke about being added to some list. But by the same token, they wouldn't even think about actually concocting such a plan.

EDIT: I want to reiterate that they should not admit any of this and vehemently deny it. That is the difference between living under a dictatorship, or living under complete freedom from surveillance and government oversight, while enjoying protection from kidnapping and ransom.