Just because Goldman Sachs would make an amazing profit if Venezuela actually made good on their debt doesn't mean they don't own Venezuela debt, right? "Goldman Sachs has not and is not lending Venezuela any money" is patently false.
GS is buying debt that someone else had. That other group loaned Venezuela money and is now selling the debt at a discount.
Critically if GS did not buy the debt Venezuela would have exactly the same money and exactly the same obligations so the fact GS 'owns' the debt or bob the accountant owns the debt is only important in so far as GS can apply more pressure.
