A child dying robs them and the world of 60+ years of human life. An 80 year old dying of COVID-19 was not going to live much longer anyway, so the loss is less severe. Old people have already had the opportunity to live a "full" life.
Imagine two societies – one where a disease kills 50% of < 10s every year, and another that kills 50% of > 70s every year. Which society would do better? Which society would you rather live in?
In the US, more people in the 55-74 age range have died than the 85+. Those are people who are taking care of grand children, or are still working. These are people that society has spent decades making fully functioning parts of society. A child has had none of that investment.
A society of just children wouldn't work, just as a society without wouldn't work.
Is your goal to just be as misleading as possible in this conversation?
Yes, of course more 55-74s have died – there are far, far more of them than there are >85s. Normalized, COVID is far more lethal (8x more lethal) for >85s than for your range. Here's the mortality rates:
In a QALY sense, yeah. The most valuable to society are the workforce but children are almost as valuable.
My parents are 60+ yr old surgeons. They work during the pandemic not because they have to. It's because you run the QALYs and the morality is clear. You participate or make way.