While that is true, doing so doesn't endanger the plane as a whole. This is Hawley's basic point.

"They ought to let everything on that is sharp and pointy. Battle axes, machetes ... bring anything you want that is pointy and sharp because while you may be able to commit an act of violence, you will not be able to take over the plane. It is as simple as that,"

...

"The air marshals and the flight attendants have legitimate concerns, certainly, for their own safety, but the threat of taking over a plane with a small, sharp instrument is zero," Hawley said. "You cannot necessarily prevent violence on an airplane, but that is not the TSA's mission. TSA's mission is to prevent a successful, catastrophic terrorist attack, and you cannot get a successful, catastrophic terrorist attack with a small knife or a Wiffle ball bat."

I think it makes sense for airport security to focus exclusively on things that could result in a "successful, catastrophic terrorist attack" ... let the airlines create more restrictive rules if they believe they are necessary to safeguard their staff (e.g., the battle axe scenario).