Of course the argument changes if herd immunity can’t be achieved, it directly and explicitly changes the speculative calculation of how much harm is caused by allowing Covid to spread quickly and how much relative harm is caused by lockdowns.

The argument isn’t over whether there is a total harm reduction goal, the argument is over which of several strategies actually leads to total harm reduction. The stated goal of lockdowns was exactly the same, to reduce total harm.

> The stated goal of lockdowns was exactly the same, to reduce total harm.

I disagree. Lockdowns were targeted, "naive" harm reduction: the harm directly caused by the virus itself. It just implicitly assumed that the harm from the virus simply had to outweigh any other possible sources of harm, and/or that other sources of harm could just be mitigated, but we had literally no reason to be certain of that at the time, and in retrospect that seems to be false.

The GBD was specifically couched in terms of total harm reduction, calling for us to account for economic, mental health, delayed treatment, and other harms caused by "naive" harm reduction policies, like lockdowns. This is the argument that doesn't really change even if herd immunity is taken off of the table. This exact argument is the opening sentences of the GBD, so that's the central thesis, and removing herd immunity doesn't change this argument.

Edit: to be clear, obviously removing herd immunity changes the threshold where harms prevented by oppressive policies are outweighed by the harms caused by those policies, but it doesn't change the existence of this threshold. Infection still provides protection, even if it doesn't convey immunity, so the GBD could still be true even if you remove all references to herd immunity.

> The GBD was specifically couched in terms of total harm reduction

So were the lockdown, mask mandate, and social distancing policies. We had far less severe lockdown than China in explicit recognition of the potential harm of more severe lockdowns. Again, the idea to reduce total harm is not unique to either side here, you can disagree all you want, but almost everyone is interested in reducing total harm, the debate is over how to do that, not whether.

BTW who are you quoting with “naive”, and why do you believe taking some action to reduce death during a pandemic is naive compared to a Libertarian backed idea to do nothing and let nature sort itself out? With hindsight, we actually know now that the GBD’s suggestion was naive because immunity rates after contracting Covid are not as good as they hoped for.