This part of his essay is wrongheaded. It was doctrinal prior to 9/11 to not fight hijackers as they usually wanted money or passage somewhere - nothing worth dying for to stop. On 9/11, once it was realized that the hijackers were bent on suicide terrorism, the passengers of Flight 93 fought back.
And ever since passengers have walloped attempted hijackers on the spot.
You're absolutely right. I remember telling people shortly after 9/11 that terrorists all over the world are probably cursing the names of the 9/11 hijackers ... because hijacking an airplane and using the passengers as bargaining chips is no longer a feasible method of carrying out a terrorist attack.
"Fighting back" is only practical when you have a reasonable sense of how lethal the threat may be. No bank, for example, would ever advise its employees or customers to "fight back" in a robbery -- even if the perpetrator isn't clearly armed. In that particular example, there's almost no cost to letting the perp get away and tracking him down later.
-PJ