Why would we close school during a normal flu season? I don't recall ever reading about a shortage of ventilators, PPE equipment, ICU capacity, morgue capacity etc during a normal flu season. Do you? According to the CDC during the 2018-19 Flu season, which runs from approximately October - April, there were approximately
34,200 deaths from Influenza. Since our first case in US, I believe reported on Jan 21, we have over 43,000 deaths and we certainly haven't seen the last of it yet. So more deaths over a shorter period and there were no social distancing required during that Flu season. To many people it will never be abundantly clear that the closing of the schools saved lives. We can only see what happened after the safety measures were put in place.
It seems that a lot want the virus to not be a big deal after looking at the real data of what is happening.