Serious question: are you stating that the reason we do not see 50,000 deaths per year in the US due to terrorist attacks is because the NSA keeps that from happening?
I think he's trying to pose the question that he thinks his opponents would ask, before they ask it.
But AFAICS no one is claiming that terrorism left unchecked would cause 50,000 deaths/yr, so really it's more of a strawman (and in poor taste too, IMHO).
Nope, because 50000 deaths/(50 plots/10 years) is too large of a number.
I don't think the NSA prevents significant amounts of American deaths. That means that these programs are all pain for practically zero gain. (And, consequently, ambivalence about them is dangerous poison.)
