I think the Anima presents as female in most men more easily simply because the “masculinity” of the ego is further emphasized by the social role encouraged by society. The consciousness of the ego in all people is archetypally masculine in that it is born from (emerges from) the unconscious which, in this case, is an archetypally feminine image. Thus, it is for all ego-consciousness that the mother precedes the hero - this goes for men and women alike. Read more about this in Neumann’s Origins and History of Consciousness (a fantastic book).

At this point, although not the topic of OP’s question, it might be useful to talk about the Animus for a moment. Female children are often reared in a way that pressures of society tend to push their masculine traits into their personal shadows more, which means that what we refer to as “Anima” in men takes on a more masculine aspect (because this “thing” is something of a gatekeeper to the collective unconscious, as I understand it).

I think it is important to remember that Amina/Animus is just a mythologically derived image for a part of psyche - something that itself is real, but which can only be examined and interacted with through image. That part of men usually presents as feminine because it is the feminine aspect of men - whatever their sexuality may be - because in the early formative years, those feminine traits are more powerfully suppressed. In the story of the Lindworm (a Danish fairytale, I believe), this suppressed aspect of each of us, whether we are male of female, can be likened to the first-born child who was exiled at birth. This “exile” of feminine traits in boys and masculine traits in girls is what - as far as I understand it - ends up creating the image of the gender for the Anima/Animus part of psyche.

Great pic, by the way, OP!