I don't see anyone suggesting that early and vast testing prevented a spread.
Of course early and vast testing helps to slow the spread. You can ID and isolate people before they spread it to other people.
I didn't say it didn't help. I said debating that misses the point.
We have NO idea how many Americans (or Italians) have been infected. The only data we have is how many Americans who have been tested have the virus.
Basing a death rate on that is completely false.