Stoicism as a whole concept seems to be geared towards a more male audience.
The philosophers being quoted are almost exclusivley pictured as bearded elder men.
(It's because that's who they were, of course. But it's still something that will probably have an effect on who feels interested.)
Also our society traditionally expects men to "keep calm and keep it toghether" more. Something that can be archived in a healthy way using stoicism.
Not saying this is a bad thing, just a bit of speculation from my part.

Also if you think women are "more passive" because of your personal experience maybe don't use words like "biologically". This annoyed me so much it brought me out of my natural lurking state :-P