Yeah... I wish I could have that ignorance but trust me. These people exist out in the world and while they are more prevalent in some places than others they use that policing of language and the sort of "normalcy privilege" as a weapon. Take my hometown, right now there is a concerted effort by these people to influence the school board and town council decorum insisting the labels cis/hetero/allosexual and allistic should be treated as slurs and make their usage an offence for which one can be ejected from chambers or have their jobs threatened.

I know a lot of people in my community who have been challenged, even yelled at in public, in person by these people because they were overhead them using cis / het to describe either themselves or others in a private conversation that these people picked up on.

What these movements do is enforce a double standard on queer communities. There is a concerted effort to rob us of the language to refer to other states of being other than ours in ways that are judgement neutral. This often causes queer friendly scholarship to have to mince through ridiculous hoops making it much more difficult to sussinctly explain concepts which otherwise become much more arcane without the ability to use adjectives.

Trying to talk to these "cis is a slur" people it becomes very clear that they do not think there should be a word for them. Their existence is assumed correct, unremarkable and beyond the ability to comment on. Our existence however is controversial and thus deserves a derivative label.