This conversation has gotten ridiculous very quickly, as just about every discussion on this subject seems to do. The pro-surveillance side of this thing has exploded with strawmen and hyperboles. This is what I'm seeing right now.
Anti-surveillance side: Surveillance and government secrecy are being taken to extremes that are not healthy. Operations like this should not be kept so secret from the public. Millions of people are caught up in this thing and denied any knowledge as to why, when, or how, with potentially great consequences to those people and the state of our society in general should circumstances shift at all. This kind of thing tends not to work out well in the long-run, and all previous comparable instances of these things happening are now pointed to as real-world examples of dystopia.
Pro-surveillance side: THE ONLY ALTERNATIVE TO THIS SUPPOSED EXTREME YOU REFER TO IS THE OTHER EXTREME WHERE ALL SECRECY IS ABOLISHED FOREVER AND EVERYONE AROUND THE WORLD HAS FULL-TIME ACCESS TO EVERY BIT OF GOVERNMENT DATA ABOUT ANYTHING FOREVER. YOU MUST BE INSANE! Plus, there are legal processes to these things that keep them within acceptable bounds. There might be a little corruption here and there, but it's self-correcting. So you don't need to worry, because I assure you this military-police-surveillance state is nothing like any of the other military-police-surveillance states throughout history. It's all there to protect you for realz this time.
That is how I would sincerely summarize the tone and content of the arguments I'm seeing.
We (or rather, the USA) don't trust government with such information. Or rather, there are extensive regulations and laws governing its use.
U.S. legislation is supposed to be subject to democratic processes that ensure public will is able to influence it to at least some extent. How can this apply to legislation that relates to something completely hidden from the public? How can there be trust that these regulations are designed and executed in good faith?
It's 100% authoritarian stuff. The essence of it is "We're going to do this thing that gives us potentially absolute power over you. We're not going to tell you anything about it, even after you find out about it on your own. You just have to trust us because we say so. Period."
I can't do that. Never going to work for me. Ever.