It may be even simpler than that. Once it is clearly known throughout the country to even the most low-information/low IQ person that this works, it completely removes the teeth from this pandemic. That means the country can open up and quickly return to normal. They want to prolong this as long as possible to further damage the economy and force Trump to open it up when there's still a few people dying. Then they can claim "see, now he's really got blood on his hands."