Whereas Argentina, a nation which only exists due to a colonial empire taking adverse possession of (already populated, unlike the Falklands) land, and whose entire claim boils down to "it's kinda near me and I want it, someone who never administered it promised it to me" is definitely morally right and justifies the forced expulsion of the only permanent population an island has ever had.

Not exactly an uncommon take. Settlement is pretty much how the world recognises national land claims.

Given all humans immigrated from Africa originally. Settlement is really the only claim any nation can use beyond force a very colonial method.

I'd agree the British 1690 landing claim is weak and colonial. But Argentina has never controlled the islands for more then justnover a year. So impossible to argue settlement. France were def the first to build a settlement their. Followed by the UK and then Spain. Given Argentina only had a presence as a nation from 1932 to 1933. They really have the weakest claim of any nation.

That said raising the islands seems to be the Argentina politicians equivalent of immigration. A subject used to distract the population from their own screw ups.