Suppose we were at war with a hostile adversary, and that adversary had killed over 700,000 people already, and thousands more each day.
I can scarcely believe that any reasonable person would argue that blocking propaganda or misinformation that harms the war effort would be an egregious imposition on free speech. Once the imminent threat is over, those efforts can and should stop, but not while the destruction is immediate.
Covid-19 has killed more people in the United States than US combat casualties every war since World War 2 combined. It is the the worst mass casualty event any living American has ever experienced.
Why is it unreasonable that serious and extraordinary measures should be taken? Misinformation about the pandemic has surely massively contributed to that death total. The chilling effect on free speech is worse? No, it's not. It simply isn't true that free speech won't return. But those 700,000+ and counting dead are not coming back.