Comparing the number of cases without reference the size of the population is meaningless.
No. Again, that is stupid and wrong.
If you were to plot expected cases based on R0, or try to determine R0 from the data on the number of cases, at no point would you need the population number of the country.
Try to pay attention. The conversation was about comparing the numbers between two countries, Iran and the US and the numbers are meaningless in that regard without also looking at the size of the populations in those two countries. To compare how bad the outbreak is the relevant statistics are infections per capita or deaths per capita, etc.
Now you're talking about TIME, and that's logical-- RATES in a given period. To that end, a quick glance at the latest stats shows the US has reported five times more cases in the last 24h period that Iran has, and our proportion of the population infected is now 73, compared to Iran's which is 245, But the TIME factor reminds us that just a week ago that number of 73 was SIX, so it's grown more than twelvefold. In a week.
As a matter of perspective, not only have we accrued infection numbers well past Iran's but we've eclipsed Germany as well and are barely behind Spain. The only countries above there are China and Italy. A week ago (or whatever period you like, a day, a fortnight etc) we were nowhere near that position.