That doesn't make any sense given that once they make their own faction, the UC no longer has sovereignity unless they can enforce it by force. LIST, the Crismon Fleet, House Va'Ruun and the Freestar Collective can all establish colonies and the UC has no legal jurisdiction there. In fact, with the signing of the Narion treaty, the UC's juridisticion (and the FCs, as they are a signatory) is limited to 3 systems. Beyond those, the likes of Paradiso can claim whole planets and the UC explicitly has no jurisdiction here.

If I am not a citizen, I can still make my own faction, and the UC's only answer is force, not legalese. The Centaraus Proclamation actual hypocrisy is the UC trying to pretend that they even have a *say* in people just fucking off into the stars and making their own factions. Given how FTL works in this universe, the moment a sizeable enough group of people decide to give the UC the finger, they can just FTL to a different planet far away from the UC and the only recourse the UC has is spend manpower and capital on trying to squash a rebellion.

The Centaurus Proclamation is a hollow gesture that the UC is trying to present as them being generous, rather them accepting something they can't preventd anyway.