Earlier quoted context omitted.
Is Chinas' reaction also not a response to terrorism? Also by war he likely doesn't mean "official" declaration of war by the vocal cords of the US president. He likely means a more physical form of war by means using soldiers, bullets and bombs to conduct mass slaughter. That kind of war.
Killing millions of people is not a proper response to and isolated terrorist act. Moreover you are trying to justify the suffering of people by using some hypothetical scenario that hasn’t occurred.
I don't think he's justifying anything. He's questioning the nature of this world where a clear black and white decision is not always possible. He is saying in this case could there be No justifiable action possible?
The hypothetical scenario is likely to help you empathize with the events from the chinese perspective. You cannot relate to the people reacting to terrorism in China. However, by envisioning a similar/equivalent scenario in your own country can possibly help you identify with the situation from their perspective. That is the purpose of the hypothetical.
The question still stands if the posed equivalent situation was happening in America, what is the appropriate response? I don't know how to answer his question, do you?
>Killing millions of people is not a proper response to and isolated terrorist act
Don't play with words here. Millions are missing in concentration camps getting reeducated, this isn't actual genocide. This is not equivalent to sending the military to another country and conducting actual killings. What China is doing is still atrocious but quite different then literal slaughter.
Also it's not a response to one isolated incident. Several terrorism acts with hundreds slaughtered and no end in sight is what is actually going on. I don't think you would call several 9/11's happening on american soil isolated terrorist attacks. Perhaps terrorism attacks in China seem isolated to you but this is not the case to a Chinese person.