Man, ppl who object to being called “cis” just straight up confuse me. The existence of a category (even one I’ll defined or that you think doesn’t have much epistemic validity) implies, at least for the sake of discussion, the existence of not-category, which can be helpful if you want to discuss anything related to the original category, or just distinguish specific concepts! Do they object to other oppositional unmarked classifications being applied to them or to other people, like “straight,” or “white,” or “male,” or “adult,” or “healthy,” or “alive”?? Or do they just object to language being an effective vehicle for communication?
The primary people you see objecting to this are just people who reject or at least dislike transgenderism as a thing, and thus are annoyed about a whole other word being created to describe what they prefer to conceptualize as “regular people”. That is, I think they’re more objecting to the use of the term or at least its use in “polite company” rather than to having it applied to them specifically? The fact that it’s a somewhat whimsical term that rarely appears outside of trans discourse probably exacerbates this – notice that mainstream trans-positive statements almost never use the term “cis” because it still has sort of an aura as a “university word”. (I wonder if “heterosexual” had a similar reception originally? I could see it going either way.)
95% of the time it’ll be that, but then there’s also a separate category of objections that criticize “cis” because it’s a conceptual void. That is, “cis” is just the residual bits left over after you define “trans people” so it doesn’t have a lot of coherence in itself. As a result “transness”, being the side with definition and the one that the people who use the terms are interested in, has a tendency to absorb any sort of complex relationship with or understanding of gender, leaving “cis” as a kind of “other of the other” that exists only as a negation of all the stuff people talk about otherwise. This of course is largely a byproduct of the fact that, as I mentioned earlier, “cis” is used exclusively by trans people and trans allies in talking positively about the trans experience and negatively about the cis experience, so in a sense this whole second genre of complaint just boils down to not seeing one’s self in the way one is defined by other factions. And from there hence all the turf wars over control of language.
Some further reasons that people may be inclined to object to the use of “cis” –
That is, “cis” is just the residual bits left over after you define “trans people” so it doesn’t have a lot of coherence in itself. As a result “transness”, being the side with definition and the one that the people who use the terms are interested in, has a tendency to absorb any sort of complex relationship with or understanding of gender, leaving “cis” as a kind of “other of the other” that exists only as a negation of all the stuff people talk about otherwise.
I can’t really say whether this is a problem that anyone has – I’d believe it, I haven’t personally seen it – but there’s a problem that is almost the precise opposite of this. “Cis” may or may not come across as under-specific to some people, but it can sure come across as over-specific.
By which I mean: the construction of ideas like “trans” and “gender,” as they’re used today, have a lot of conceptual infrastructure and scaffolding. There’s a lot of fairly-detailed worldview behind them. This worldview is, trivially, not universal. The easy thing to say on that score is that a lot of Gender Fuckery from other times and places, the stuff that produced two-spirit people and Roman “male brides” and Persian eunuchs etc., did not use remotely the same categories or the same underlying concepts. The harder-but-also-true thing is that a lot of people today, in our own culture, don’t use or like those categories or those underlying concepts.
And while it’s one thing to say “we are a community of people who do conceive of gender in this particular way, it’s important to us, and we are going to put that front and center in our public-facing nomenclature” – it’s quite another to say “our conceptual structure is going to define the nomenclature and the categorization for everyone who isn’t us also.” It’s like…you imagine that goths started using the word “htog” to mean “does not have the goth-nature,” and started making a lot of pronouncements about what htog people are like and what htog-ness really means, and justified this on the grounds that it’s important to be able to talk about things. There’s a clear sense in which this is true, and another clear sense in which htog-ness is not a particularly meaningful category outside one particular human context with an idiosyncratic focus. If someone told me that it was important for me to consider myself htog or to identify myself as htog when accounting for myself to the public, I would be annoyed, and I think justly so.
This ties into a related issue, which is the unfortunate power politics of terminology.
In briefest terms: the liberal West has spent the last sixty years or so being told, over and over again, that it is extremely important for human dignity that groups be able to control their own labels and nomenclature. Being told, by outsiders, “you’re ‘cisgender’ now, the world has decided this for you, your opinions on the matter have not been consulted and are not relevant” – well, at best it’s a reminder of the asymmetries that are baked into certain kinds of identity politics, because more-fashionably-oppressed groups have screamed bloody murder whenever anyone tried to do anything similar to them, and the cultural establishment* has stood behind those complaints. And those asymmetries carry an awful lot of baggage, for obvious reasons.
*to the extent that this is a real thing, but you take my point
And a very minor point that I think comes up seldom, but I have in fact heard it from some older folks: “cis” was in fact once used as a childish euphemism for “urine” (in circumstances where “piss” was too vulgar, comparable to “pee”). If that’s a thing that sticks in your mind, it’s not hard to see why being called something that amounts to “pee-gender” would rankle.