And it looks like even the dumbest/worst herd-immunity scenario is still quite far from a catastrophe. Which is pretty good news IMO.
Pretty good news for the ones who survive you mean?
How is this different from a "Human Wave" strategy in a war?
Some of you will die, we can't predict who but likely people in the first row but we need everyone to participate to make it work. Not everybody will die, so it is not a catastrophe but some of you will likely have long-term trauma and lost limbs. So that is pretty good news overall and I as the general making it happen will get a medal for bravery ("or get elected" or "remain in power", etc).
Leaving the ethical/moral considerations of making people play a Russian Roulette aside, the above is justifiable ONLY if the alternative is an even bigger catastrophe. This is why you see the ideological or self-interested "libertarians" who aren't exactly on the front-lines spreading FUD that it is.
In the most optimistic estimate for herd immunity in the US (roughly 60% spread, about 0.5% CFR), some 1.2M people will die if my math is right. Pretty good news? Compared to what? Not being able to go to the hair salon? Children starving in Africa (which was happening even before)? Mom and Pop shops going under (unless countries do loose fiscal policies aimed solely at them rather than largely reward capital investors as the US seems to be doing)?
You combine bad fiscal policies influenced by lobbies with bad mitigation policies on an undisciplined population and you get ... the US.