True enough, and it is quite possible that there are inbuilt tendencies towards violence that are more prevalent in men than in women. But statistics can be misleading, because there are other factors as well as genetics.

For example, if statistics showed that in a particular society members of a particular ethnic group had a relatively greater tendency to commit some offence, or that some nation appears to have a history of aggressive war, it is not valid to assume a genetic explanation.

And modern war isn't so much about people wanting to be violent, but more about people willing to order other people to do things which have violent results. Storming into battle with a fixed bayonet or a blazing gun might appeal to some kind of atavistic blood-lust, but you don't need that to issue orders. And it is clear enough that army training methods are capable of producing women who are capable of acting as efficient and lethal military personnel.