isshoes
Or can women not be a term for everyone who identifies as a woman, and in the context of discussing transgender issues, the term 'cisgender women' be used to denote people who do not consider themselves transsexual?
I (personally) have no problem with changing the definition of woman to include transwomen. I do have a problem though when certain transactivists, having secured that change in definition, then go on to say that e.g. reproductive issues are not women's issues and that therefore it's transphobic for the women's movement to focus on them. And that does happen.
And the problem with "cisgender" is that it's a term for one group of people, invented by another group of people, which is always problematic. And further, the people who invented that term are largely born male, and the people described by it are largely born female (as these discussions always seem to occur between transwomen and other women). A course of surgery and some hormones notwithstanding, it's never cool when members of a dominant group seek to define members of an oppressed group.
The other problem with cisgender is its meaning - dictionary definitions point to something like "an unproblematic relationship between one's sex and one's gender" or "a feeling of gender fitting with sex". But within the group of women who are not trans, there are plenty of women who feel that is an inaccurate description of them. For example many feminists believe that as gender is entirely a social construct designed to uphold the patriarchy, describing someone as cis is basically the same as saying they love their chains. And then there are plenty of women like me who have lots of stereotypically masculine traits but identify as women, not transgender. Cis is a really bad description of what I am. Trans is too.
If someone calls you cisgender and you're not, perhaps just say 'actually I'm not cisgender'. And the world will move on.
I guess it is the same as if someone mixes up (say) transgender, transsexual, or transvestite. If it's done in ignorance, you correct, you move on. If someone does it to be deliberately obtuse or to show they have no respect for the way you choose to describe yourself, if they do it dismissively, if they do it to show they don't care, then that's offensive. If you want to describe someone's relationship with gender, and you're not sure what it is, why not ask?