Okay, the purpose of battles is to kill people. Who cares? The point is that just because the purpose of x is y, and you want y, does not mean that you must accept all forms of x.
Very rarely. The purpose of a battle is to take and hold ground, usually. If you do it without killing anyone it's still a victory. A lot of Gulf War 1 was fought this way, the Iraqis took a look at Western tank divisions and simply surrendered. Another reason is to degrade the enemy's ability to fight subsequent battles. You could do this by destroying all their equipment and supplies. If you do it without killing anyone it's still a victory. An example of this is catching an enemy's air force by surprise and destroying their planes while still on the ground. The Israelis are masters of this technique.
No sane general wakes up and thinks, I just want to kill some people today, I don't care about strategic objectives.
