Really? Who were they? Is there any evidence whatsoever to back this claim up?

It does if the argument is about colonialism.

No one lived there before Europeans arrived.

But if the islands were empty before? Like there's islands who have thousands of years of history of people living there. But then there's also those who just doesn't. Are they supposed to stay empty? All humans always bad, or something?

Eh, nobody else was using them for anything.

You've still not explained why Argentina should be allowed to colonise it and Britain shouldnt.

Literally no one was there when France landed there, so you can either a) ask France and Spain for their thoughts, b) resurrect the Fuegians who visited and let them have it, forcibly deporting the people who've lived there for centuries, or c) disregard pragmatism and say they aren't part of any country – either way, you can stop obnoxiously trying to defend Argentina's baseless colonialist claim under the guise of "anticolonialism".

To the extent it belongs to anyone, it obviously belongs to the UK far more than it does to the asshurt losers who flaccidly tried and utterly failed to assert sovereignty over it.

They belong to me.

I have as good as a claim on the Islands as Argentina.

Funny how quick the anti-colonialism argument got abandoned when facts entered the picture.