You were comparing number of cases and number of deaths on the same date in time.
I pointed out that you need to compare the number of cases 14 days ago with the number of deaths now to get a more meaningful percentage. Percentages are therefore considerably higher than you extrapolated.

I don't disagree with most of your other statements to a degree but there is a big difference in comparison with modern flu.
Yes, an estimated 650,000 people die every year worldwide from flu, but the first H1N1 flu pandemic was responsible for 50-100 million deaths in the first 2 years. The population is now almost 7 times what it was then.
Surely that is some indicator of what would happen if you just 'let everybody catch it' as you appear to be suggesting.

Oh, surprise, that 50-100 million people was 5% of the earth's population. Just about the same percentage as are dying now out of the positive tests.
Yes, we have no idea how many people are asymptomatic or immune. It might be many. It might actually be zero.
I actually suspect it is a pretty high number. Just my opinion but I can't believe a virus first identified in China in mid December took 2 months to develop into the first known case outside that country, given the sheer volume of Chinese that travel and the way the numbers have escalated since the first case. All that said I still think lockdown is the best way.