It's basically the same thing as when Trump drew the hurricane on the map to an area where it wasn't going, and then fired all the people at the NWS who corrected him. Sticking your neck out and stating the emperor has no clothes is a fast track to getting replaced by someone who will play ball. Trump is exceptionally petty and has some paranoia that there is a “deep state” trying to undercut him. He doesn’t accept that these are professionals trying to do their jobs, because he is a moron who thinks he knows everything, better than the experts, and they are just trying to undermine him and make him look bad.
Trump is a uniquely stupid and incurious president, and he has absolutely no interest in listening to experts. The only people he allows to be around him are yes-men. He doesn’t understand what’s going on, and he doesn’t particularly care insofar as it makes him look bad, and tanks the stock market (makes him look bad).
Even Boris fucking Johnson is astonished by how bad the administration’s response has been.
In short - we elected a narcissistic, incurious, anti-intellectual, paranoid con man to be president, he is now facing a real, serious crisis, and he’s busy purging the career professionals that we need to be solving this crisis. He is that boss who can’t stand not being “the smartest guy in the room” even when he has no idea what he’s talking about, and he’s in charge of managing our response to basically Spanish Flu 2: Electric Boogaloo.