This is just my personal speculation, but the KFA has been aware of the internal conflicts within the national team for some time

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Since Klinsmann showed absolutely no sign of resolving the issues,
they brought in Hong Myung-bo to try and patch things up with his charisma,
but that didn't work on the younger players.
As a result, the disaster at the World Cup occurred,
and the Association faced heavy public backlash.
They then brought in a foreign manager of the tactician type that football fans would welcome,
but instead, the situation has become even more fractured.
Could this be what is happening?