The means are justified because they’re proportionate, and that makes them moral. That’s the moral foundation of war.

How else would means be justified, except by ends?

The phrase is “the ends don’t justify the means”; it’s particularized. Those ends don’t justify those means. Other means may be justified. You don’t use an axe to remove a fly from your friend’s forehead, in the ancient Chinese proverb, but you might use a rolled up newspaper. The ends justify some means, not others.