In fairness to guy Star Trek fans, I think they do realize that women are at least half the fandom and have leading roles within the fandom. The problem comes from the societal stereotype of geeks, which erases women. After all, according to stereotype, there is only one kind of woman, which is why Disney can’t animate any other type. Why Big Bang’s creators thinks that women would need to have Star Trek fandom explained to them. And why non-fans like JJ Abrams can’t see the huge female fan base.
Exactly, the problem is when these societal views and stereotypes are accepted as the truth by the people creating not only Star Trek but other media - who then think the only demographic they have to appeal to is 18-49 year old men.
So do male fans realise how many female fans there are? Or the roles we’ve played? If they do then why don’t the people in charge?
My personal experience has been that guy Star Trek fans, even ones I dislike, have been perfectly aware of the size of the female fanbase. But that’s just anecdata, and I don’t know if any actual studies of attitudes have been done.