Or even as simple as a procedure:

(1) search for the applicant on google/baidu

(2) if the searches reveal support or sympathy for dissident or seditious activity, deny the visa application.

It's actually quite surprising how un-integrated US government agencies and systems are.

not that integrated, as matter of fact until last few years and maybe still even nowadays labor bureau database was not linked to Visa EEB database, so i could get work permit on invalid visa although they should be strictly linked

i guess they are quite thorough only when it comes down to dissent (though my wife in gov job hit immediately career ceiling after marrying me and everyone around her even newcomers kept growing except her, sure just coincidence /s and we both can't still really publicly say what we want because she has there parents and rest of family)

One would think, but at the same time knowing the bureaucratic garbage that happens at tech companies (and I would think communist party HQ is a bit worse), I imagine their system is likely a giant mess and it probably took a number of months to get back about the visa.