I love science and I'm pretty much a science guy, but scientists don't know everything. It's impressive how knowledegeable they are compared to centuries ago, but there are lots of things scientists don't know (particularly biologists and docs). I know a girl in epidemiology, it's a complicated field. Virus can mutate and without reliable data, it's hard to understand. China didn't provide many reliable data (to avoid the blame game), so it didn't help to understand this shit.
Also, there's always a balance to find between safety and economical/social issues. It's a very complicated problem, and scientists can't make this arbitrage: we elect and pay politicians, people with responsabilities, to do that. Their job is not easy.
Remember H1N1? France bought 90+ million vaccines (we are only 60 million) for NOTHING. People got angry against them, saying that they wasted money. Arbitrage is tough. Few people are cut out for this. There are always bad consequences in a choice. I don't blame our government. They did the best they could do. As for scientists, not all of them knew what was gonna happen. Far from it! (and they still don't know how it will evolve - though they are more knowledgeable now)