An 1,180% payout - for basically buying and holding out in bad faith - wouldn't be endorsed by any U.S. court if the affected party were American (case in point, Detroit - where the courts pushed back a vulture fund attempt to hold its own restructuring hostage).
But by paying the ransom voluntarily, Macri's basically endorsing the practice of sabotaging third world debt restructuring - which both Democratic and GOP administrations have been adamantly against (expect with Iraq; but then it's the least Bush could have done).
That's the real reason they like him. It's not - as some business opeds claim - economic (U.S. interests in Argentina did much better under the Kirchners, thank to the strong economy at the time); and it's not strategic (Argentina has almost nothing to offer the U.S. geopolitically, and in fact Macri has been happily lending himself to Bibi's ploys to try to sabotage the U.S.-Iran talks - a key Obama initiative, as you know).
Macri killed the Kirchners' successful debt restructuring (92% acceptance, and the bondholders ended up making money!) - and by extension, any future such restructurings by other developing countries. That's what was expected of him. We can't very well let third world countries think they can ease their own debt burdens, can we now.