Because of the manner in which the NSA conducts upstream collection, and the limits of its current technology, the NSA cannot completely eliminate 'about' communications from its collection without also eliminating a significant portion of the 'to/from' communications that it seeks.
I wonder if that would work for me. "Your honor, I had to rob all of those banks because I could not afford the Lambos and prostitutes that I seek."
Of course the government would have to eliminate such a program that gathers what it seeks... because what it seeks is unconstitutional!!! How the fuck did they write a 191-page report and completely miss that point?! I'm sure there would be a ton of people ready to cite Hanlon's Razor, but nobody is that dumb. If you still don't buy into that, then let me introduce Organgtool's Razor: In a world where everyone buys into Hanlon's Razor, all it takes for evil to triumph is for it to wear a veil of stupidity.
Intel CPUs are not defective, they just act that way. -- Henry Spencer