"If we do that, how are we any better than those we are fighting?"

The title question is asked by people too stupid to ask it, much less answer it, about World War Two, say.

Too stupid to understand that if we don't differ on means we still differ on ends, and our ends being so much different they remove all reasonable doubt that we are different, exactly in a way that matters hugely.

And that would be true even if the Machiavellian Principle were false that for any means, no matter how bad, there is a possible purpose so good as to justify it.

Even if the Pauline Principle were true that we must never do evil that good may come.

Though of course neither is true.

No moral principle is true.

Nor indeed, is any false.

And though one still might find it better to follow - or that others follow - the one than the other, there is nothing to say preference might not vary from case to case.