Well, I can agree that trans people should not be subjected to persecution for being trans while at the same time disputing the distortions of current trans language.  And I can only speak as a woman, but specifically, if trans activists need a word that means women who have not transitioned from another sex, then they might try the obvious, clear language:  non-trans women.  

The central problem with creating a category like cis women is that it presumes women with two X chromosomes all feel the same about gender when in fact, women are pretty diverse in terms of how they embrace and express gender.   Indeed, fighting to relax gender stereotypes has been a big part of women's progress over the past decades -- it's not so long ago that schools required girls to wear dresses and take home ec.  It's not like trans women are the only ones who have struggled with the constraints of gender roles and expression.