I am well aware the scanners are flawed. However, I have not seen a study that shows the added benefit is "indistinguishable from zero." Please provide links, I may agree with you.
All I can do is point to the zero deaths since 2001 caused by passengers smuggling dangerous objects onto planes. Flying is far safer than many other common activities whose risks we gladly accept, and that would remain true even if terrorists blew up a fully loaded 747 every year.
"All I can do is point to the zero deaths since 2001 caused by passengers smuggling dangerous objects onto planes." - As I noted above, we have recently had a few close calls. It appears the terrorists are adapting. Personally, I'd rather we try to stay ahead of them than wait for your sentence to change to "well we had zero deaths until 2011 when ..."
"Flying is far safer than many other common activities whose risks we gladly accept, and that would remain true even if terrorists blew up a fully loaded 747 every year." - I have used this argument myself (yes I have argued your side as well). However, it does not capture the broader impact - economy etc (this may be why they continue to target planes). Frankly, I think the terrorists could accomplish their goals in many other far easier to accomplish ways but I wont help them here.
I understand your view. I just don't share it. You attacked mine by saying the scanners added zero value. I forwarded a link that while critical of the scanners also noted they were as "effective as a pat down". Unless you think pat downs add zero security, then we are back to security vs personal privacy.
“While officials said [the scanners] performed as well as physical pat downs in operational tests, it remains unclear whether the AIT would have detected the weapon used in the December 2009 incident,” the Government Accountability Office (GAO), Congress’s audit arm, said Wednesday in written testimony to the House Homeland Security Committee.
And not specifically related to the new policies, but see here for plausible analyses that by inducing travelers to drive rather than fly, the TSA is on balance killing Americans: http://www.flyertalk.com/forum/travel-safety-security/115092...