The argument isn't that we can choose between economic shutdown or preventing the spread of the virus. It's that we choose between economic shutdown or the spread of the virus and economic shutdown.
Indeed they are already doing it, the opposite of being terrified.
Especially in Sweden who has no full lockdown.
I think you may be watching too much mainstream media which is filled with fear based reporting.
I'm quite risk-averse and started as a total "doomer" in this. When it was clear that we were seeing an exponential process with highly unknown effects, I locked down hard, even before any states or organizations were even discussing it. I'm still in that state, because our household is "old" and has health problems.
But, time has passed, and we're getting a lot more information about this. One thing that's starting to look clear is that people under (say) 50 aren't being killed by this in large numbers. The only reason for them to lock down or act in atypical fashion is to prevent them from spreading the virus to the old (or those with significant medical issues).
It's reasonable to ask whether we could not better protect the elderly by far more targeted measures. Yes, that might cost a lot, but locking down the economy seems to be both costing a lot more and likely less effective in reducing the death count.
Beyond that, it's entirely possible that if we could get most people under 50 to catch the virus (while keeping the elderly safe from it), society would achieve herd immunity and then the elderly would be far more protected than they are under current actions.
Simply shutting down the economy is a holding action. Clearly "flattening the curve" for fear of hitting the ceiling on hospital beds, etc., was worth doing. But now we know a lot more, and have a far wider range of reasonable options. Just being shut down does nothing in itself but delay the inevitable deaths.
A vaccine? Maybe, but it's a real long-shot. We've never had a coronavirus vaccine before, even though there's been a lot of work on it, and it's quite possible that we won't for decades.
We are learning more about treatment options, and that's good. But the clock is ticking and people are already dying from the shutdown itself. It's morally unacceptable to say that those people don't count. Every death matters.