The term cis is used for a very specific purpose. A White person might well object to being called White because, honestly, that’s just the societal default! It’s always been us, and you know, those other guys… Of course, that’s patently bullshit. Having a presumptive norm and then an explicitly labeled Other communicates a clear centering of one perspective at the expense of others. I’m sorry if you don’t like the term Cis. I don’t particularly care for Woman, but I don’t get to top-down reinvent the English language on a whim (we feminists tried that and it flopped spectacularly). Now that Trans people have managed to finally carve out some cultural intelligibility, the term Cis has caught on and will stick around. I get that this isn’t always comfortable- being labelled by others without your consent sucks. That said, the choice is to reject it and thus alienate Transfolk and their allies, to embrace it despite your misgivings, or to coin something more comfortable and hope to hell it catches on.