Apart from the fact that there is still substantial (if less) risk to younger people the real reason for lock down is to reduce the spread.
It's proved impossible - even with very strong measures - to protect at-risk groups by isolation. See both Australia (where a very large number of deaths were in supposedly isolated nursing homes) and Sweden (same).
As an Australian, your second point is hard to vindicate. The total death toll in Australia is 106 as of one hour ago as reported by the state-funded ABC[0].
While it's true that just one of those was a person under the age of fifty[1], and unfortunately I live in the _one_ state that's experiencing a second wave via community transmission and sadly expect these numbers to grow, this isn't comparable with the numbers seen coming out of Sweden.
In fact, it's an order of magnitude lower, for a country with more than double Sweden's population, so to suggest that at-risk groups are experiencing a similar level of risk is baffling to me.
62/106 deaths from COVID in Australia have been in nursing homes[1][2].
The point isn't that Australia hasn't done well (it has!). The point is that even in the best possible circumstances it still proved impossible to keep nursing home patients safe.
In Sweden the plan was to keep nursing homes isolated too, and it didn't work there either.[3]
Sorry about missing you were down under, I only checked after hitting submit. And thanks for clarifying, I had no idea Sweden moved to isolate nursing homes.
That said, I'm still hesitant to equate the risk level to the elderly from community-wide lockdown measures with isolation policies restricted to nursing homes. I don't have any data to support it, but I can't help but assume that lower community transmission overall correlates with fewer transmission vectors into nursing homes. Supposedly this would turn up in the proportion of those in nursing homes that's suffered coronavirus. In principle I agree with you; the hotel scandals in Vic bear that out, ironically, and sadly. But the difference in magnitude has to count for something, as bad as any toll is.
It's proved impossible - even with very strong measures - to protect at-risk groups by isolation. See both Australia (where a very large number of deaths were in supposedly isolated nursing homes) and Sweden (same).