Cis-yt-male here, so take my limited-perspective opinion however you'd like...
But... Wouldn't it be better to first talk to the mods of that c/?
My understanding (again limited...) is that the r/ they are modeled on (and took the name from) has existed for quite awhile, long enough to where most peeps were much less aware of trans inclusive issues back then
I wholeheartedly agree with you that trans inclusivity should be a forefront in the movement, but my 2¢ would be to start with the mods and see about changing the name/editing the sidebar to be more inclusive. It is 2023 afterall, and this is SLRPNK. I have a feeling peeps here would be very open to that dialogue