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
I think this a way for our trans comrades to express their frustrations and I don't really want them to have to bottle it all up since they do that so much through out their whole lives. It can also be directed at cis women so I don't think it is gender exclusive.
Personally gonna say something maybe controversial and say it's a good thing. From what our trans comrades been saying transphobia if far more prevalent than what we can see. If I get called a cissie it's a warning that I really need to have a look at myself and realize I'm making someone uncomfortable. Kind of like how snitching to the volcelpolice works, when being too horny I can forget my other comrades and act selfishly but this reminder there to keep me in check.
To address the transphobia you need something more than just policy idk changing the culture so using the phrase cissies mad might help. It's a reminder that our trans comrades safety is more important than how it makes us feel and that all of us can slide into transphobia if left unchecked.
Something similar I can point to are the things I do for the women irl I interact with. I'm a big guy so I can be kind of scary looking so I try my best to be salient of this. I make sure I'm not cornering someone when talking to them, make noise to make my presence known, sometimes not head somewhere if a women is walking in the direction I'm heading so as not to freak her out and etc. Yeah I feel kind of weird doing this but making women feel safe is more important to me.
Same here if trans comrades use this more and more good. I hear you about feeling bad about this but if it makes them more comfortable and they stick around good. Also we become salient to our own privilege and it keeps us from sliding into tranphobia since from what our trans comrades tell us it's far more common than we think it is.