The lesson from 1918 for public health is that if you lie to or mislead the public once, even if by accident, you have reduced credibility in the future and are less likely to have the public listen to you. The authorities didn't learn this lesson and instead misled the public for 2 months, then did a 180 and expected people to blindly listen to them again.
As a citizen, would you trust the government if they did yet another 180, after demonstrating to you 2x that they didn't actually know what they were talking about?