[Someone]

Yes, you want your soldiers to survive because training is expensive, and comrades dying is bad for morale, but it is not _the_ top priority.

If it were the top priority, very, very few attacks would take place. Taking that hill, destroying that gun, or gaining knowledge about enemy positions often gets higher priority than the lives of a few (or lots of. Generals knew lots of soldiers would die on D-Day, for instance) soldiers.