Plus, the federation doesn't claim no one's land without searching for the civilisations/life-forms existing there. Indeed, no local power is portrayed as quite so negligent/lazy.
BTW, I and my neighbors can't claim an uninhabited island by hiding there. There are a series a conditions to be met - and the baku meet none of them.
Nor can I and my neighbors claim the legal system doesn't apply to me and make our own - again, there are a lot of conditions to be met; conditions the baku don't meet.