on edit: furthermore https://www.cdc.gov/flu/about/keyfacts.htm says the range of people catching the flu per season is 3% and 11% whereas the estimates for catching Covid-19 are generally around 40-70%
Flus are often widely deflected by inbuilt immunity. The advice didn't take that into account. It also doesn't take into account those numbers are based on pretty flimsy evidence.
the second number will decline after everyone catches it, obviously.