You're wrong, because anyone--male or female--who can't score 180 points on the PFT at the male standards doesn't have the stamina for doing the job for extended periods of time. A female soldier may be able to dismount a 90 pound main gun barrel, once, but to ask her to do that, plus dismount the gun itself and tote ammo for extended periods of time, with minimal rest makes all it a different story.
We haven't even touched on the point that stress and fatigue effect females emotionally much differently than males. I had little contact with female soldiers, but I did get around them enough to see them cry like babies, because they hadn't gotten their beauty rest. Or, their ***** hurt because they've been working their asses off for 20 hours straight. We certainly haven't gotten into how they have to go back to contonement, or even the rear, every other day, to wash their nasty crack when they're on the rag. it's an Army regulation, BTW, that female soldiers who are raggin' have to be allowed to take a hot shower every other day. How's that going to practical in a combat arms unit that is 200 miles away from a building with actual hot and cold running water?