Argentina has defaulted on its debt nine times since 1816. It isn't really a fault so much as a strategy. The reason they can keep getting loans from US banks after so many defaults is that the US banks which make these loans are able to get bailed out by the US government.
So is the fault Argentina's? Or does the problem lie with US banks that know they can't lose on the loans they make, because the guys who own the banks also run the US government? The banks get the interest payments from Argentina and then they get compensated for the lost principal by the US taxpayer.
You know, if a bank loaned me money and I defaulted, and then the bank came back the next year with more loan offers and I took the money again and defaulted again, and then the banks came back the third year with more loan offers, I'd be stupid not to take the free money.