The only reason a lot of cis people think being called a “cis person” is bad, or harmful or wrong is because they are used to the privilege of just being seen as a “person” or even a “normal person” without their sex or gender or gender identity being an issue for them. You see, when you call them “cis” suddenly they are not just a person, but now they have to think about a gender identity. Suddenly they are no better than a Trans* person. And that scares the shit out of them.
(Source: lezzbfriends, via tal9000)