The difference is that flat earthers reject objective evidence. This is someone disagreeing over projections about the future. And, to be frank, nobody has a fucking clue how to estimate the medium term effects of this.
But we do know certainly that we will only be hitting the peak of infections sometime in April in states that were much more proactive than the median. It is extremely unlike that things will clear up, say, by Easter. Those who are so optimistic are innumerate and don't understand exponential functions.