There are a couple of more parts to that story that help to make it more persuasive.
1) Zero succesful airline attacks
2) Zero convictions for attempted terrorism of anyone detained by the TSA
3) Zero civilians killed in any form of (islamic extremist) terrorist attack on US soil in the last decade or so (all the way back to 9/12 if you don't count the borderline case of John Malvo).
The point being that not only is the TSA not stopping attacks on airplanes, it is also not doing such a good job that it would redirect those attacks to other targets.
1) Zero succesful airline attacks
2) Zero convictions for attempted terrorism of anyone detained by the TSA
3) Zero civilians killed in any form of (islamic extremist) terrorist attack on US soil in the last decade or so (all the way back to 9/12 if you don't count the borderline case of John Malvo).
The point being that not only is the TSA not stopping attacks on airplanes, it is also not doing such a good job that it would redirect those attacks to other targets.