I think it’s a reference to r/fffffffuuuuuuuuuuuu a very old, established subreddit for rage comics memes. Then when the trans meme subreddit became a thing, they copied the style of the name. Then they brought the same name over to Lemmy.
There are other subreddits with the same style name, like r/iiiiiiitttttttttttt for IT related memes.
I could be wrong, I wasn’t there for the formation of the /r/traa subreddit, but that’s my speculation.
The trans community is kinda really nice, in other parts of Lemmy and Reddit usually when you are wrong about something even in a non-malicious way (say this first-handed lol), you get downvoted to the abyss, it's refreshing to see such a peaceful community, btw, some user below commented that it's a reference to the r/fffffuuuuuuuuuu subreddit, pretty cool!
Nah the worst is when you don't find it relatable or even understand any of it and people insist you do and poke fun at you (egging) sometimes going a bit too far, that happened to me. Wasn't fun, but I did eventually figure out about being Agender (and Isogender) which really cleared up the mystery of why I don't understand gender. Just kinda wish people didn't try pushing the stereotypes so hard on me, was real frustrating and uncomfortable ya know.
Btw I know I'm replying to old comments, been gone for a while and trying to catch back up.
Don't worry about it too much, just egg_irl/traa humor, lots of them like to poke fun at the idea of turning people trans but it's a joke (it's meant to be a joke, though sometimes people violate the prime directive and it becomes not funny anymore).