There's spying in the abstract, which is known just from the existence of intelligence organizations, and there's spying on specific targets (or everybody), which hasn't been subject to public scrutiny or debate until now.

It's one thing to "know" from movies that someone is being spied on. It's another thing entirely to know from NSA documents that you and people you know are being spied on.

I'd like to suggest that! We wouldn't have done 90% of the evil, pointless, counterproductive bullshit we've done since WWII, if all aspects of that bullshit had been public. And, not a single genuinely good thing we've done would have been prevented.

Details of military battles could be kept secret during the battles and for a couple of years afterward, and sure we should keep demographic data about private people restricted to only those agencies that legitimately need that data, but those are the only exceptions that come to mind.