What's that have to do with the price of fish?
There is a huge difference between repeated swinging just a few pounds of weight and wearing even 50+ pounds of well distributed weight over your body.
Believe it or not, in general women are as readily capable of either as are men. It's more of a question of training the body to it than any particular inherent physical traits. Even considering the average 36% greater muscle mass in men compared to females.
I think the strength stats of men and women are two curves that intersect somewhere, but the mean and the extremes (especially at the higher end) are not equal.
This means that there is a threshold in terms of muscular effort that if you get past that threshold, consistently, a greater proportion of men will be able to manage it compared to women. This is why for most sports, you have a separate category for men and women.
I go to work with 2 workstation-class laptops in my backpack, their chargers and a bunch of other stuff. In the total, the weight is ~30lb. I can manage it just fine. I'm a 6f1 guy who strength trains and weights 240 pounds (with 20 in extra, my ideal weight would be around 220).
In general, they don't recommend you carry a backpack that is more than 20% your body weight.
That means that for most women at the office (whose natural weight gravitates in the 110-140 lbs range), my backpack is too heavy. Could they really push themselves and manage it? Sure, however, they'd probably hurt themselves in the long run (that's the thing with resistance training, you can push yourself past your natural threshold, but you tend to hurt yourself if you do it). Does that mean no woman should carry my backpack? Hell no, some women are stronger than me. It just means the average most women shouldn't.
Similarly, in terms of aggression, the vast majority of violent criminals are men. Doesn't mean a woman can't go on a killing spree, it just means on average, men have a lower threshold for becoming violent.
Looking at gender asymmetry, it's not really a wonder for me that the majority of battlefield combatants have been men historically.
However, I'm not sure why some people think that's a bad thing for women. I personally view a greater reluctance to bash someone's head in with a hammer as positive and more socially adjusted.