I think this is misunderstanding the point. It's not that we can't protect the most vulnerable, it's that we can't protect them particularly well IF community s

I think this is misunderstanding the point. It's not that we can't protect the most vulnerable, it's that we can't protect them particularly well IF community spread is high. We are partially effective in protecting the most vulnerable, e.g. through restrictions on nursing homes. But, infections in these communities still correlate with the level of community spread - e.g. if you halve the new case rate in nursing homes with restrictions, but you double the new case rate in the community, you may be back to where you started. The point being, as you allow significantly more spread in lower risk populations, you'll have a really hard time keeping higher risk groups at their current level of transmission risk (which, in the US, is already a fairly high level of transmission risk).