Some can't. But that is not the primary reason why women shouldn't be in combat portions of the military. The primary reason why is because apart from rare exceptions, they simply cannot match the endurance and power of men.
There is a reason why there are women's sports and men's sports.
Women have always been in the military, as cooks, washer women, nurses, supply and camp followers “Hookers” They just—with a few exceptions—didn’t fight. When Mehamed II captured Constantinople—in the final attack—all fought, women too. Many cases of prostitutes with the French Foreign Legion picked up arms when outposts were attacked by Riff tribesmen in North Africa. Attempts to form combat units with women has not worked well for the USSR and Israel. Women have done well as pilots and in the many office roles in the Modern armed forces. In truth, women are too important to risk in combat.
a large number of jobs in the military do not require extraordinary endurance or power. We have always had less-physically-capable soldiers who did jobs that needed to be done, and in the modern army, these jobs sometimes make up the majority of the “fighting force”.
The suggestion that a female shouldn’t be the secretary that handles a commander’s work schedule because other soldiers will assault or kill her seems off, and I don’t think you are suggesting that only a muscle-bound 6-foot male could answer a telephone.