The two aren't mutually exclusive, obviously.
I am reluctant to kill millions of innocent people.
Although all too willing to do so in the instances I mentioned above (in Japan and Germany in WW2).
We are at war against countries that sponsor terrorism.
Precisely, and that's why the Saudi "holy" cities of Mecca and Medina would be annihilated in the event of a nuclear attack by Islamists on the U.S. As in Germany and Japan in WW2, destroying those cities would have the effect of breaking the will of our enemy. .....And it would probably succeed.
Again, cut the moral superiority crap and start living in the real world.