Invisible enemies, external threats, and fear of disease are very effective at implementing authoritarianism. It gets the victims to enthusiastically endorse their own gulag.

In Nazi Germany, Hitler started out with legitimate and good public health efforts including cleaning up against tuberculosis. The problem was it escalated and didn't stop - they had to start cleaning out the people they perceived as sources of various impurities in the society.

It is happening all over again. It is very effective - scared cowards are ready to hunt the unclean and those who are not like them.