I've been holding off on making this post because I didn't want to distract from the trans issues that have been front and center on this site recently or be accused of concern trolling or tone policing. But since those issues don't show any sign of being resolved any time soon, I'm just going ahead.
I don't want to be the cis equivalent of a white person who gets big mad about being called a mayo or whatever. But it seems to me that the intention behind the term "cissie" is that A. it creates an equivalent to the t-slur to turn around on cis people and B. is intended to trigger the toxic masculinity of cis dudes by essentially calling them "sissies".
Fortunately, I'm not very invested in being a "masculine" guy. Unfortunately, I had a lot of experience having my masculinity policed growing up for being too effeminate, not liking the things I was supposed to like, being too emotional, being "f*ggy", you name it. While I definitely don't think it's intentional on the part of our trans comrades, being called a "cissie" in a hostile manner (as with some of the "CISSIES MAD CISSIES MAD" posts that go around this site) really triggers those feelings.
For me, it feels like being a white person who is called a mayo, except I actually spent my childhood being pelted with jars of mayo.
Edit: At the advice of @breadandcircuses, I want to be crystal clear that this not a call out post or or an attempt to tone police anyone. Making fun of cis people is cool and good. I react badly to a specific term and this is the fault of patriarchy, not our trans comrades. I posted here in c/menby because I know that there's a lot of chapos who deal with similar issues
thank you, comrade <3
<3