The real issue is close to this. The real issue is that when the organization is empowered it's up to an individual to say "no" to improper surveillance. That's what's wrong with the "well there are good people behind it and we are all on the same team" argument. When it becomes your job to prevent an attack, and you have the authority to spy more than you think is morally correct, do you spy anyway? Or are you willing to let 3000 people die, and face the music of the world knowing that you could have prevented it but chose not to for altruistic reasons.
That's why the laws must change: to protect the people who want to do the right thing.
To play devil's advocate, if everyone in the U.S. gave $1 to a fund to help the world's poor, that'd be $314 million in aid. Nothing to scoff at, even though it wouldn't end global poverty.
But in any case, I'm not sure if your example is analogous, because $1 from a person is incrementally helpful, whereas having that person's phone data is almost certainly not. This brings me back to the grandparent poster's anecdote -- I don't think that the NSA would have been able to stop 9/11 just by sorting through everyone's texting and phone calls. It just seems infeasible to really deal with all of that information unless the attackers were very obvious through their conversations -- correct me if I'm wrong.
Did someone seriously say that to you? Did you rebut with "would you give $1 to end poverty globally?"