Could this explain why all these governments are taking such drastic actions?
Well, right now that question requires a lot of 1+1 assessments, speculation, and reading between the lines.
The starting point is that China is an evil nation with a history of murdering or oppressing its people, and a history of dishonesty, and is a deeply proud nation. Given that it would be embarrassing and deter global trade and tourism, it seems easy to conclude that China has drastically downplayed the seriousness of this disease. It has simultaneously ordered a strictly enforced quarantine over much of the nation and taken rather brutal and extreme measures to enforce it.
There is at least some evidence to support the theories of significant more seriousness and illnesses and deaths.
* The doctor who discovered it was arrested and detained and silenced for a period of time as an anti China propagandist.
* Widely reported that a lot of incinerators are working frequently to burn in infected areas.
* Widely reported that people are being taken away never to be seen again. Youtube bloggists are among those disappearing.
* Media and information blackouts.
* "incorrect" larger numbers reported and then downscaled.
* Internal leaked reports indicating massive under-reporting.
And it's easy to delve into whether this was a accidentally or nefariously leaked bioweapon experiment from a lab in Wuhan. Go over to the conspiracy thread for that one.
The numbers in China, particularly the 5% fatality rate between dead and recovered populations, don't match other 1st world nations much higher fatality rates. So that's an obvious tell they have cooked the books.
It's my theory that China quickly (early January) knew or saw (or both) how lethal and contagious this was and went into quarantine mode. Other governments must know and followed suit.
For a trivial flu, this is in fact an over-reaction. But if it's a horrible contagion nightmare, the lock downs all make sense.