In about less than 4 years it will be shown this was used for completely other purposes against political enemies, but accepted because they were your political enemies. And then it will be used against you, after which there's an outrage thread and "how could this have have happened???" posts.
This is correct. There is no logical reason or empirical evidence that opening country to mass immigration will help fixing native birth rates. Problems such as housing will just increase as there's more competition for a 5 square meter flat.
There is no reason to believe that 'immigration' can fix the native birth rates of South Koreans. This is an implicit assumption dreamt by the utterly deranged.
Given month of incubation time (from when you catch it, and are asymptomatic, but still spread it), it's not unreasonable to assume for sake of alternate models it's been spreading since November and people just thought of it as case of particularly bad cold. Only know of it since it got too big to hide by Chinese govt.