Given gender is a set of socially-constructed, narrow stereotypes, it is anatomically impossible for a gender to 'match' one's sex. Upon further questioning, no one who's claiming this is the case has yet been able to explain how it is the case.
We are constantly told 'cis' is not a slur, that it simply means 'not trans'. This is wrong. It's a chemical term, meaning 'on the same side as'. In which case, my above point applies.
I'm stuck with my sex. I have the body: anatomy, chromosomes, physical form, skeleton, muscle density, and hormonal component of a female. Manufactured gender (which is very much real albeit a construct; to deny as much is to deny women's perennial struggle) has been the cause of my oppression. I've spent my adult life claiming my sex is irrelevant to the way I do my job, for example. Why the hell would I want to 'identify' with the instrument of my own oppression?
These are particular issues in my Stonewalled workplace. I will not declare 'my' pronouns (which I don't own), and I will not accept being called 'cis'. I don't consent to having this label foisted on me. I'm not a believer, therefore I don't accept using the language of a belief system to which I don't subscribe.
So I'm now having my reasons for this rejection foisted on me instead. 'You want to define yourself as "normal"'. Equates to: 'you are othering trans people as "not normal"'. Equates to: 'you are a Bigot'.
I know perfectly well that such motivation has never been mine, but the courtesy demanded from me is strangely enough rarely extended in my direction.
It's merely becoming tedious now. I don't require validation of my identity from others. Nor arguments about my own right to assert my preferences (or not, as it happens). Nor to reject labels people are arbitrarily imposing on me. Nor to declare my protected characteristics. All I want is to go about my working day in peace, to maintain my privacy, and to focus my energies on my actual work.