China had an extensive system to delete disinformation. Every IM, UGC website or app are required by law to provide a report button and ICPs are required to response to user complaints immediately. There's also national wide hotline 12377 or website 12377.gov.cn to submit all categories of information you want to disappear. Any bad content esp. those against-govn't ones contained pretty quickly, which means not only…
The only thing they need to do is that if a post that went viral is debunked, they need to show a retraction to users that have engaged with the fake content.
Deleting the content means some people think that it's a conspiracy ("they don't want you to know"), whereas giving corrective information allows people to revisit their beliefs.