> Perhaps they could allow mass immigration to fix it but that would destroy the culture. The issue is happening everywhere, how is it racist?

Well, there are people that think the idea of preserving cultures itself is racist (well, at least western ones), or that there is no detrimental effect to an existing culture by enabling mass migration.

> Perhaps they could allow mass immigration to fix it but that would destroy the culture.

This is the racist part. The majority is always worried about how awful everything would be if they were to become the minority. Usually it's because they treat minorities like shit, and they'll worried that they'll suddenly be treated that way too.

Why would that possibly destroy their culture? Are the cultures of all minorities always destroyed? Why would that be? Is it because of racist assholes?

It's an incredibly weak argument when you think about it. The South Korean culture doesn't have to go anywhere: there will be the same number of Korean pop stars and artists and chefs as there was before, it's just that there will also be others coexisting with them in the same country. Somehow this is a huge threat? They're worried about their culture being "watered down" by lesser cultures? These are racism-adjacent fears, similar to their pure blood being mixed with the lesser races. If you're worried that the South Korean youth will get so much exposure to other cultures that they somehow drop or forget the Korean culture, that just feels like weird gatekeeping and more "mixed blood" concerns to me.

Is there a limit on how much culture can exist? If so, it's surely based on population. We're not talking about the South Korean population declining more due to immigration; it's already declining. If their culture is in danger, it's surely due to that, rather than some sneaky danger of all those dirty immigrants. How is it not based in racism? We're just talking about more culture overall.

Not to mention the fact that most culture spreads over communication channels, not physical bodies. Those terrifying 8 billion non-Koreans who are threatening to destroy Korea's culture are already influencing Korea's culture. Would it really make that big of a difference if they were physically within its borders?

The racist part is thinking that the confucianist misogynistic hyper capitalistic culture is worth protecting in the first place, as if Bangladeshi, Indonesian or Filipino people living in the same country as you will somehow be the thing that is the end of "Koreanness" and not all of the culture's inherent issues itself- the other kind of end of Koreanness (the implied preferred end) is when almost everyone who is Korean dies out. (Which, to be clear, is not limited to Korea- it's the same set of issues everywhere people complain about "immigrants")

I'm not saying there's zero problems. Both too-rapid population growth and too-rapid population decline can cause problems with social stability and economic systems. I specifically called out doomerism.

South Korea's birth rate is indeed dangerously low and threatens their economy. If they cared they could do something about their extreme workaholism and cost of living.

As far as immigration destroying the culture: it depends on the rate. A healthy but limited rate of immigration revitalizes cultures, but it's pretty clear that sudden mass immigration is dangerous and causes a lot of problems and backlash.

Speaking of fixing problems... if our billionaire class who seem so worked up about birth rates wanted to do something about it they could also address the most frequently cited problems preventing young families from forming. Like housing prices.

If we really get into a situation where dangerously low birth rates are threatening the economy and social stability, the boring solution is to do what we do for other goods and services that the free market isn't adequately providing: directly subsidize it. Pay people to have kids. The easy way would be a payment or tax rebate to married couples with 0 children to have one child. But that's the boring solution that doesn't involve massive reactionary cultural transformations, so the right-wing "problemists" won't like it.

Edit: by problemism I mean people who use a problem as a lead-in to push only one solution, and they're not actually interested in solving the problem unless it's their solution. An example from the left side of the spectrum would be Marxists for whom any solution to climate change that doesn't destroy capitalism is unacceptable, or anarcho-primitivists or anti-tech trads for whom any solution that doesn't involve shutting everything down is unacceptable. In reality the solution to climate change is to emit less carbon, and physics doesn't care how we do that or what political system we are using.

There's a lot of right-wing problemists for whom any solution to excessive population decline that doesn't involve taking rights from women and re-introducing reactionary theocratic or nationalist structures isn't acceptable.