The New Yorker's Mayer is paraphrasing an anonymous source, which she then counter-points in the very next sentence of the article with a quote from NSA historian Matthew Aid, who says: “The resistance to ThinThread was just standard bureaucratic politics. ThinThread was small, cost-effective, easy to understand, and protected the identity of Americans.” [1]
I think if you read my comments you'll find that I'm not denying that ThinThread had a goal of protecting the identity of Americans. The problem is that the collections programs underpinning PRISM and XKEYSCORE also have that goal. The problem isn't the technology.
That's what Binney and Drake have said all along.
[1] http://www.newyorker.com/reporting/2011/05/23/110523fa_fact_...