There's no need to research the why. The only point I'm making is the end result - which they used as the main base of their argument on, is not true. Why it's not true is likely very complex, but it's not true.
Nobody is going to be grateful for something that didn't happen, why would people be grateful for dying less as a population, if they in fact did not die less? Also there were lockdowns all over the world, not just in the US.
I'd be curious to see rates by country by BMI and infection date. There were definitely lessons learned from Italy's early surge that helped other countries in the early days.