In a word: awful.
In more words: it's like peering into the mind of an almost alien species. The way ciscentric people privilege their own view on sexes and genders is just breathtaking. They try really hard to believe they can get the sexing-at-birth -bit right, when it's bloody obvious to me they can't.
They also don't seem to recognise this. Acronyms FTM and MTF are a nice case in point: why the hell would the initial mistake be relevant in categorising people? It's like calling a divorcee a wife-to-divorcee - as if the first bit was somehow relevant to what she is today.
Cises don't want to admit they're cis - they'd much prefer "normal", for which there's the very handy counterpart "abnormal" which is reserved for riff-raff like me. Using words like "woman" to mean "cis woman" is a nice case of this.
Then there's the bit how the cis don't seem to get it's a different thing to be a girl than to like girls: the conflation of sexuality with sex/gender is pretty common, too. They're related, sure, but if you like to peer into that more closely, I think it's easy to notice it means there's a lot more genders and sexes than two - if sex/gender and sexuality are linked, it kinda means lesbians are a different sex from het women...
...and it means that the words homosexuality and heterosexuality lose their meanings, too. For how can one be homosexual if there's no opposite, or same with regards to sex/gender? We're all heterosexuals, but that means the word "heterosexual" doesn't denote anything on top of "sexual" any more. Words like "androphile" and "gynophile" and "sapphophile" would be more meaningful, perhaps. Once you mess around with the binary, you do lose a lot of words, and there are very few, if any, alternatives. I find it very telling that both "homosexuality" and "heterosexuality" are used without questioning so widely even in gender studies, where otherwise gender is seen as something more complex than either woman or man.
Oh yeah, it makes me angry as a hornet, too.
4 hours ago