I don't like conspiracy theories, but seriously it looks like they are trying to lessen the numbers on the paper instead of really trying to find the patients. Compare the numbers that the countries are testing[0], US is less than a thousand and Japan is about 1300.
Edit: Just for people who are curious in how things are working in South Korea, we test everyone who has: pneumonia symptoms, or has been in the same place with already discovered patients for free - and anyone who is concerned can test with about $100 - which is refunded if one turns out to be positive. We track every COVID-19 patient's routes and test everyone who was in the same place; which means that the government (mostly) knows exactly how the virus is being spread. Based on data that was announced 10 hours ago[1] (we announce data and roadmap twice every day), we have tested 66,652 people with 1,766 cases found, and currently 25,568 tests are on-going. 1,727 people are being quarantined, and 26 people have fully recovered from COVID-19.
Second Edit: Okay, I'm not really skilled in English; if this felt like bragging how South Korea is well handling this situation, that is not my intent - we have a lot of complaints of how the government should handle this. My intent was asking why the US/Japan is not doing at least this much, considering that both countries are much powerful & richer than Korea. Both countries are basically the Korea's wannabe-countries; and everybody here is pretty shocked (literally - there is a lot of news/SNS posts/internet memes on how Japan/US is handling the situation) that they aren't doing well.
[0] https://i.imgur.com/BAROczt.jpg
[1] http://ncov.mohw.go.kr/tcmBoardView.do?brdId=&brdGubun=&data... (Korean, sorry :-()