I think the question isn't whether we're overreacting or not (we'll never know the counterfactual), but whether our reaction produces the correct results. It seems to me that taking extreme precautions, even if in error, produces an outcome that is the lesser of evils. Let's look at scenarios for favoring not "overreacting": (this is your camp)
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1) If you don't take extreme precautions (overreact), and COVID isn't worse than the flu = hospitals don't crumble, economy doesn't tank, life goes on.
2) If you don't take extreme precautions (overreact), and COVID is worse than the flu = hospitals crumble, economy is destroyed, many deaths occur, and our way of life is over.
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You're gambling that (1) is true. If you're right, great..... but if you're wrong, we'll end up with (2).
On the other hand, here are the scenarios for the "overreacting" gamble (what we're doing now):
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3) If you take extreme precautions (overreact), and COVID is worse than the flu = hospitals don't crumble, economy tanks but things eventually settle and there's a path to recovery.
4) If you take extreme precautions (overreact), and COVID isn't worse than the flu = hospitals don't crumble, economy tanks but the virus fizzles out and things eventually return to normal.
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This latter gamble, though expensive, provides us with a path to safety regardless of if we turn out to be right or wrong about COVID. Because we don't know enough about the virus and given the exponential spread we have to act on incomplete information, I would be in the camp of "overreacting".
That said, I do sort of understand where your sentiment comes from. It is a position reinforced by a (healthy) distrust of media sensationalism, and recognition of the widespread human suffering that results from the economy tanking. I think that's a reasonable position, and one that I'm sympathetic to. However, the cost of being wrong here is just so unspeakably high that there's just greater prudence to choosing the latter (safer) path.