i believe part of the reason could be that men tend to be more aggressive and women tend to be suppressed. there is also the notion that tech in general is a man's field and also safe spaces for women in the blockchain world have not been created. also there needs to be more role models so that other women can aspire to be like them.
I agree with you, maybe in this are male has more advantage than female. However this doesn't mean that women ca't involve in bitcoin. As long as you know the information carefully, you will know how to invest in bitcoin to make a profit.