I dont think that's what he's saying either.
Effective security comes way before the departure gate. If that is our main line of defence no amount of security will foil the inevitable.
I think what he is saying is we should look on these as successes; ok a guy got onto a plane with explosives. But it was a desperate move, with little chance of working - and it failed.
Yet actually it succeeded because now the TSA (and others) are running scared again.
It would take a brave politician to turn round and say that this time the system worked. The heightened security meant a desperate mechanism was employed and the "last line of defence" (passengers) were utterly effective.
Abdul Mutallab could have used his butt (or other things, like a prosthesis or a wheelchair) to stash the parts necessary to assemble a relatively reliable bomb. That's a known attack type, but we're not defending against it at the security checkpoints. Now that could be a wise decision based on the fact that checking for it is hard and, as you said, "effective security comes way before the departure gate".
But if some future terrorist carries out this quite-plausible attack and the government then decides that the TSA should start screening for it, it'll mean they learned nothing from the underwear bomber.