Are you trying to make a salient point, or are you simply being contrary?
Off the top of my head (and in my admittedly uneducated opinion) one of the reasons you don't see as many female mass murderers, probably has a lot to do with the basic hormonal/physiological/psychological differences between men and women. On a fundamental animal level, males and females are quite different. In all species.
I would go on to theorize that these powerful mind altering drugs affect the sexes differently, as well. Fair enough?