Wrong. The terrorists did not break their laws when they committed their acts. They broke our laws, but not necessarily those of their state(s). God's law (according to the Bible) clearly states "Thou shalt not kill." Therefore, to break the law of our nation and commit such a crime, is to also break God's law.
The World War II example devastates your argument, therefore you falsely claim it to be a "red herring." You do so because you cannot refute it.
An objective reading of the Bible and of the history of Jewish, Christian, & Muslim nations suggests that God allows a lot of leeway in admonishing us not to kill.
Your World War II example is a perfect red herring because it does nothing to address the assertion that the terrorists acted out of religious conviction.