After further thought, the former head has another good point (although maybe accidentally)...

The way the policy is now (restricting only certain knives), you actually put MORE burden on the TSA. Now, the TSA has to stop what they're doing and distinguish between 6 cm and 6.5 cm, or whatever the line of different is. Whereas before, all knives were banned and the method steps were simpler: (1) See a knife; (2) confiscate the knife.