Double standar, my friend: when it comes your way UN´s always gonna be fine. When it asks you to re-start conversations over some way away south atlantic islands they´re just a mob of puppets, decided to support a dictatorship that ended 32 years ago...
Umm actually, I don't give a #$% even when they back our decisions, if I had my way we would pull out of a lot of UN conventions. That said, it might evolve into something in a couple of hundred years, if we last that long.
Now we can go back and forth saying you did this wrong in the past, hence it entitled us to do this, but when does it end.
The case of the Falklands is the local people who have been there for generations, don't want to be Argentinian. From their moral viewpoint its all that matters. Maybe Argentina should concentrate becoming a country they wouldn't mind being part of.
So it comes down to two reasons that Argentina wants them, economic or nationalism. If its nationalism, then nobody really can claim the high ground, if its economic, I understand, but you really need to find a legal way to obtain them.