One country is conducting mass testing, the other is not. Florida alone does about 4x as many tests per day as all of South Korea. South Korea's testing didn't tick up until a few weeks ago and that's exactly when their cases started rising.
They appear to be going about it smarter, too. Seems Moon Jae-In ordered testing be done with rapid antigen tests last month.
The Korea Herald is pushing the "gold standard" of PCR, but rapid antigen are quicker and more reliable at catching infectious cases, those with higher viral load, than the PCR standard used around the world which is finding completely healthy, noninfectious people as positives. To quote the article:
The rest of the world's been running those tests as high as 45 Ct, as suggested by Drosten last year. Fauci himself said they're meaningless for detecting infectious cases above 35 Ct.
That the article is trashing rapid antigen accuracy and pushing SK to go the PCR route is a giant red flag. That's propaganda at play, half truths used to deceive.