Good grief! You don't put women into combat because they're too dangerous!

Fighting among men is about asserting dominance. For most men, all that's needed is for the other guy to quit fighting, either by surrendering or doing a runner. With all-male armies, massacres are the exception rather than the rule, and are usually the result of intense anger at something the enemy has done, or equally intense conditioning or brutalisation of the soldiers. In WW2 the Wehrmacht and non-Russian Allied forces were generally only modestly barbaric. But the highly-indoctrinated Waffen-SS were instrumental in many massacres, as were the deliberately brutalised Russian troops.

Women are reluctant to fight at all, being more risk-averse and less biologically aggressive. But when they do, they fight to kill, and they fight to kill all the enemy, regardless.

Any man who has ever gone up against an all-female team in a paintball or laser-tag match will know just how sneaky and utterly ruthless they can be. The ladies play for keeps!

But in a war, you need to keep all the options for flight, surrender and negotiation open. Again, it's about dominance, after all.