It could also contain non-public domain data, and you can't declare someone else's intellectual property as public domain just like that, otherwise a malicious actor could just train a model with a bunch of misappropriated data, get caught (intentionally or not) and then force all that data into public domain.
And to complement your answer, the place where a custom firmware might still be compromised is mostly in the binary blobs, where proprietary code for the radios and some other chips aren't open-source and act like some kind of black box between the software and the hardware and make it work.
Unless someone reverse-engineer those blobs and make an open-source alternative.
From what I understand, Clubsall doesn't allow federation to go both ways and accept that users outside of its domain can participate freely in their communities.
Can't have it both ways of leeching the posts from other large instances while simultaneously making it an exclusive club where only local users can participate, it goes contrary to the social contract and spirit of the Fediverse.
Merry Christmas you filthy animal.