The Japanese test displayed suggests that they were not even expecting anyone not Japanese to achieve it ...
Anyway, I can only imagine that people would want to be able to repeat the content and removing the KIs for allowing so only make sense. Just like you lose the Einherjar feathers once you do the Odin fight. If that did not happen, the elites would want to keep repeating the boss fight over and over while other players keep "sucking their thumb".