I'm pretty convinced that the purpose was just to purge the sub of wrongthink. Because there's no way to question it without coming off as "transphobic"
That's pretty much how they always do it in my experience. They'll start changing small things [the sub's banner image, the icon, making troon-related flairs] to 'test the waters' and deride any opposition to it as: "whoa bro! why do you even care??? it's such a small and insignificant thing to get mad about bro touch grass", sort of like they did when someone made a mod to get rid of the troon flag in that Spiderman game. "bro why do you even care it's so insignificant???" --> "cool, if it is insignificant, you won't mind me making a mod to remove it then" --> "woah you're literally a bigot for making this!" --> *mod gets removed, creator banned, proving that perhaps it wasn't quite so insignificant after all.*
Then as the troon bullshit ramps up and begins to take over the community, any opposition or even questioning of it is discounted as if things were always that way, and the rejoinder from the jannies [and much of the community, as troons will glom on to any community which remotely tolerates them, even if they have no interest in the topic outside of making it another troon hangout] will be: "EVEN BY LITERALLY ASKING WHY THIS WAS DONE YOU ARE LITERALLY COMMITTING LITERAL GENOCIDE AGAINST LITERAL TRANSGENDER FOLX, LITERALLY! YIKES!"
Sort of like how a lot of subs will have a "no politics" rule, which may be enforced to start with but later becomes "no politics unless the jannies agree with what you're saying", as happened to r/tornado and r/weather. They still had a no politics rule yet most of the front page was constant "LE DRUMPF IS DEFUNDING NOAA/NWS THIS IS LITERALLY GOING TO CAUSE FATALITIES" bullshit and when people suggested that they didn't come to these subs for politics, they were either told "b-b-but everything is politics, e-everything is downstream of politics, and by not choosing a side you're choosing a side!" or just outright banned. Indeed, leftoids managed to make a fucking subreddit about tornadoes and the fucking weather into yet another leftoid circlejerk. It's almost impressive.
Honestly, at this point I could probably write a fucking book on some of the subs I've watched turn into a troon circlejerk, a leftoid circlejerk [they're basically the same thing], or go from being useful/helpful and informative to absolutely worthless. Especially so with r/PoliticalCompassMemes, I doubt anyone would be interested in reading it but I may write an effortpost about that sooner or later. Generally speaking, though, even the best subs, the ones where you read content there and don't even feel like you're on Reddit, will gradually get overtaken and the Redditoid menace will leak through. It usually happens whenever a sub gets 70-100K subscribers, at that point there is [typically] still some decent content but the percentage of Redditoids gets to a certain point and takes off like fucking wildfire, until it reaches critical mass. At this point I am only even visiting Reddit as a case study in just how deranged a leftoid echochamber can become and I have plenty of exhibits. Some genres of sub go to shit in a totally unique way, such as all of the video game subreddits or those related to any sort of entertainment, media, franchise, etc. For instance, pretty much every video game sub gets overrun by "cosplayers" [advertising OnlyFans whores who have never played the game that made a cheap 'cosplay' with ample cleavage out of shit they found at the thrift store] who are updooted to the moon because Redditors and "WOW MUH BING BING WAHOO AND BOOBA WOWIE!!!" since they're all mindless gooners.