The standard rumor is that the Chinese vaccines do not work as well, either at slowing down the spread or at reducing the severity of the effects, as western va

The standard rumor is that the Chinese vaccines do not work as well, either at slowing down the spread or at reducing the severity of the effects, as western vaccines (whether Pfizer, Moderna, J&J, or Oxford/AstraZeneca). So, the feared effects of having most people get it are worse than here. Also, in the US, the CDC estimates that for every 10 people who get it who were confirmed/counted, there were 32 who were not counted. Since many states have had >20% of their population confirmed, that suggests that >85% of many US states have already had Covid-19, vaccinated or not. The ratio of "immunologically naive" in China is probably much higher. Not saying that makes it a sensible or even moral policy, just that's the most likely scenario as to why they are doing it.