The time that the virus stays incubated, already transmiting, but with not sympthons, is like is was designed to break quarentine protocols.
That sayed, if it is a bio weapon, I also think it got out by accident. The lab that in Wuhan alread have problems with employes selling animals that should be euthanized.
So I think is something like Chernobyl. Someone made a stupid mistake, but fear of repercutions, delay action that could avoid the spread of the virus.