As far as I can tell from the outside, there were actually multiple overlapping cover-ups within China by different organisations with different interests that resulted in doctors, nurses and medical researchers being silenced - starting with local-level coverups that tried to keep the national government from knowing there was a problem, and ending with multiple national-level coverups, including attempts to cover up the fact the local government had covered stuff up because that in itself was embarrassing to China as a country.
That's what you get with authoritarianism. Both the carrots (political advancement) and the sticks (punishment from above) encourage underlings to obey what they think their superiors would command, even when those superiors are not involved.
The pithiest example is the death of Li Wenliang. The doctor who was threatened and silenced for warning others of a SARS outbreak, himself died of the disease when it spread due to inaction.
