South Korea is a very young democracy with fresh memories of what it was like under dictatorships. The people very much understand the price it took to get to that point and is not complacent in stomping out wannabe autocrats.
Why is his favorability rating so high?
Okay at the same time they had the daughter of one of those autocrats fairly recently as PM, who then resigned due to influence peddling by a religious advisor (and did crazy things like her daughter didn’t go to class yet got amazing grades because her teachers were made to do her work, which she posted about on social media.)
They’re very much not over those players.