In complex systems by the time you 'know' something it is often outdated information.

Coronavirus was here and replicating before we knew about it. By the time we knew about it, there was more of it than we new about.
The novel UK variant was here and replicating before we knew, and is probably even now in places we don't know about yet.

Climate change will be impacting ecosystems before we see/understand the evidence. And so on.

When there are delays in knowing the actual state of the system there's a danger that your corrective actions (lockdowns, travel bans, carbon limits etc) are responding to the world that *was* not the world that *is*.

Especially if the trend is towards worsening severity, you'll also be responding too tepidly if you respond to the latest news, which is actually old news.

You need to understand and account for the momentum of the system. Which, to someone who doesn't understand it, will look like over-reacting.

May 2021 be full of the kind of action that looks like over-reaction, but is actual just appropriate understanding of dynamic systems.