Yeah, it's always struck me as neophobia with a side of entitlement: 'I shouldn't have to learn this new word/concept because I am not the weird one here'. Plus, acknowledging it as part of one's self-concept is a perpetual admission that alternatives exist. If you asked a white, straight, middle-class unmarried young woman with no disabilities for self-identifying terms in, oh, 1960, you'd probably get white, and single, and young, and female, but you might or might not get middle-class as something that even occurred to the person, and you certainly wouldn't get 'able-bodied' because that involves consciousness of the alternatives, and you wouldn't get straight unless you specifically asked... so these days cis as a self-identifying term does indicate a certain amount of awareness of the concept of trans. And hopefully it will just become an identifier on the level of straight, where it certainly isn't adequate for all cases and has its problems, but we don't have people denying the very existence of the discourse in which it functions.