The cynic/realist would say its not minimizing casualties but minimizing negative effects of casualties.

That nowadays is necessary to win a war because society doesn’t accept as much suffering from both own and enemy forces and civilians as it used to. The USA got out of Vietnam because of lack of home support and decreased morale of its soldiers (https://en.wikipedia.org/wiki/Vietnam_War#Collapsing_U.S._mo...), not because of the enemy’s strength.