Because covid running rampant poses an unacceptable risk to social stability and therefore to the CCP’s grip on power. This is a function of propaganda they have been pumping out of the last 2 years wrt the effectiveness of the Chinese response & domestic vaccines. The policy response they have been touting as evidence for the superiority of the social contract they impose on citizens (lack of rights in favour of stability and growth) is now shown to be as susceptible as every other countries to the unescapable biological facts/reality of viral spread. This directly calls in to question the CCP’s credibility. Also Xi, needs to maintain the status quo until Q3 when he is up for re-election… It is a horrible situation for the Chinese people.