For December time frame, this is the correct interpretation. We would already see a suspicious spike in 1st-2nd week Jan pneumonia death rates if COVID-19 were spreading in the US in December. Average time to death for those who do die is I believe 17 days from onset of symptoms.
Yeah, there's just no way there was a huge COVID-19 cluster here in the US in December, and then everyone just got better and it never turned identifiable. We know how insanely contagious this disease is. It couldn't have been circulating for months in a given area without sending enough people to the hospital/morgue to draw scrutiny.
