This unhappiness is because of the lax standards the Korean government has with Chinese entering South Korea compared to Chinese regional governments putting Koreans going to China in mandatory 14-day quarantines:
Public chagrin is growing over some Chinese provincial authorities’ forcible anti-coronavirus quarantine measures against South Koreans, fueling criticism of Seoul’s cautious immigration controls and strengthening calls for broader entry bans on Chinese visitors.
Despite Seoul’s entry ban limited only to China’s central Hubei Province at the center of the new coronavirus outbreaks, Weihai in the eastern Shandong Province and other regions have enforced unannounced quarantine steps against visitors from South Korea.
The measures came after Seoul embraced Beijing’s calls for a “scientific” decision in line with the World Health Organization’s (WHO) recommendations against unnecessary travel restrictions and sent protective masks, goggles and other relief items to China in a show of unity in the fight against the virus outbreaks.
The containment move raised questions over Seoul’s hitherto cautious approach in dealing with Chinese travelers in the midst of a recent spike in the number of COVID-19 infections in South Korea, which has risen to 1,146.
“China has been consistent in its claim that travel restrictions should be made based on scientific grounds and WHO recommendations, while decrying strict entry restrictions by the United States and other countries,” Park Won-gon, professor of international politics at Handong Global University, said.
Yonhap
You can read more at the link, but the only thing I am surprised about is that people are surprised by the Chinese government’s duplicity on this issue.