I'm fairly certain that the "only" 6 digit death rate we've currently had has had a negative impact on the families and friends of the affected.
If you have been left untouched by it, then good for you, but you shouldn't be assuming that that applies to everyone.
The mortality rate in the US is 1.8%. That is 542k dead out of 29.8 million cases.
That's nearly 30 million cases with all the lockdowns, mask rules, etc.
Even with that minor amount of 9% infected, LA hospitals ran out of capacity, morgues overflowed, etc. Try to imagine if we didn't try to limit the spread - by among other things closing schools.
NZs recent outbreak started from a couple of kids in a school of only 13-1500 students, and with lockdowns that dwarf anything the US did they only just managed to control it, getting to something like 100 positive cases because they didn't want to lock down completely.
Your numbers are incorrect. The case numbers are meaningless because there have been so many infections that were never officially counted as cases. Antibody seroprevalence studies have shown that the true number of cases is 2 or 3 times higher.
Schools in Florida have been open for months and they aren't overwhelmed.
The worst-case realistic number of deaths for the US is around 1.2 million. With hospital collapses, maybe double that. 10 million is not possible.