The Republic of Korea is essentially colonized by the US, who installed the former compradors from the era of Japanese colonialism as the new government. They are dominated by descendants of these compradors called the chaebol. As such, it's a country rife with a history of struggle and instability, division, and heightened contradictions. The majority of their presidents have been either killed or imprisoned, and many of them have committed atrocities like the Gwang-Ju massacre that murdered thousands of student protestors.

The extreme beauty standards and treatment of beauty as capital comes from speedrunning this dystopian development, and will fade over time once the US Empire is kicked out, and eventually socialism becomes the mode of production and distribution in the state overtaking the ROK. This is also partially why the DPRK does not appear to have these same absurd beauty standards.

It simply lacks the stigma it has elsewhere.

People want to look good… and Korean beauty standards are obscenely high.