ANY weapon can be defeated if you play tactically against it. Even golden gun and rocket launchers. But that doesn't mean it's fine to let people strut around with infinite ammo rockets and GG. The problem is that thorn allows players to overcome or tie with an opponent who has the advantage in positioning or skill. Note that killing in two headshots isn't 50% faster than killing in three. A 2hsk is TWICE as fast as a 3hsk. And that's not accounting for the fact that Thorn is already in the fastest archetype of handcannons.