It is right to defend your child, even if it involves killing someone.
Your analogy doesn't make any sense. It's not necessary to kill to defend any child.
Wouldn't you have killed a soldier, a politician, a CIA terrorist, ... to have saved any of those millions?
No. It's not my personal responsibility to stop killers.
That's not what the US propaganda said about the German people who allowed their governments to slaughter at will. The German people had the excuse that their very lives were in jeopardy if they spoke out.
And you believe America and Germany's history are the same? Do you understand the US Constitution?