This whole "cis is a slur" idea that's running around anti-trans circles is so ridiculous. It's transparently based in a desire to declare that transgender people don't exist. I mean, it's not as if the people calling "cis" a slur object to being called "not transgender." They already decry transgender people as immoral, mentally ill, criminal, etc ... Of course they wouldn't wish to be thought of as trans!

What they really object to is the need for the category.

What I mean is, using the word "cisgender" is convenient to the point of necessity when discussing some transgender topics.

For example, it's a lot simpler to say, "Transgender gay men have been building support networks that include cis gay men since at least 1990" (which is true, btw) than it is to say, "have been building support networks with other gay men who are not transgender."

In appropriate contexts, I describe myself as a "cis gay man." It's just convenient.

People who don't like that convenience don't like trans people. They don't want trans people to exist, or they want trans people not to have equal equal human/civil rights.

By objecting to "cis" as a category of human beings, they're actually objecting to "trans" as a category of human beings. That's the point. The only point.

Not only is "cis" is not a slur, calling it one IS a slur. It's anti-trans hate speech flung about by a group of people bent on eliminating transgender people from society and from public discourse.