I remember @sgt-grunt giving me a kicking in that scenario.
Here is a contrary view- there is no passivity or recklessness, only lack of planning. You must be able to envision the course of battle before you hit the big red button, otherwise woe is you. Therefore, you must be able to calculate the amount of force you need to seize any objective. That includes numbers of men and their weapons (as well as weapon types), what indirect assets you need, what direct fire assets you need (and their routes of advance and firing positions), and so forth. If you know the algorithm for the attack/assault, you will know by inverse the algorithm for defence. Warfare is science- calculation mentioned beforehand, as well as an art- application of that calculation.