I'm pretty sure if you were involved with terrorist groups, you became aware of this sort of thing well before it made the front page of the New York Times. The idea that keeping it out of the press prevents the targets from knowing is naive.
bin laden & co. knew the NSA process took 72 hours and adjusted their communications accordingly. the operational aspects (read: deficiencies) of many "important" monitoring functions is widely known by those who "need" to know.
No one is (or should be) saying that the operational aspects can't be kept secret. The problem with this system is not secrecy in operation, but the lack of warrants before the fact and the lack of accountability after the fact.
Imagine such a system in the hands of your least favorite politician and/or party. If you're OK with that, then by all means, carry on. Some of us aren't.
Well, there are warrants. Even the Verizon records things was in response to a warrant. There's accountability as well, but we can't see it.
What I am concerned about is the transparency of the arrangement overall. But if NSA said "Hey Guys, we're monitoring Facebook and G+, don't use those if you don't want us to be able to intercept with a warrant!" then that would defeat the purpose of the system entirely. So it's a difficult issue.
I will say that I would feel better if I knew what legal & policy systems they were using to ensure accountability. But honestly we know in general what needs to be done to keep dangerous systems like these used safely, I don't think that's actually the problem. We've kept nuclear weapons and bio-weapons safe, after all. But I would feel better if I knew that NSA had those kinds of onerous formal controls on when systems like PRISM were used.