When President Biden took office, his message was clear: COVID policies would be determined by science, not politics. So imagine the surprise when the head of the Centers for Disease Control and Prevention (CDC) announced other considerations entered into deciding the new guidance on isolation for asymptomatic, COVID-positive people.

“It really had a lot to do with what we thought people would be able to tolerate,” CDC Director Rochelle Walensky told CNN Tuesday. The network’s Kaitlan Collins replied, “It sounds like this decision had just as much to do with business as it did the science.”

Former Surgeon General Jerome Adams, who served in the Trump administration, went a step further. “They wouldn’t even follow it for their own family,” he said of CDC officials and the revised guidelines.

Perhaps. But realism about how people actually behave should enter into CDC recommendations, as should other considerations that don’t strictly involve the virus. Epidemiologists can give sound advice about how to slow the spread of infectious disease. They are not experts in economics or how to organize human society. When their advice doesn’t weigh factors too, it is often doomed to fail.

Propagation of the unrealistic idea that people can be isolated and the economy largely shuttered until vaccines and other elements of the pandemic response are perfected has helped undermine confidence in public health experts rather than bolster faith in their directions. The resulting skepticism has increased popular defiance of the CDC and officials like Dr. Anthony Fauci, especially on such matters as masks and vaccines.

In fact, far from being unbiased preachers of the science, public health authorities have always been selective about what they shared with the ordinary citizens to shape public behavior. When they initially claimed masks were ineffective for the general population, for example, they really wanted to prevent shortages for health-care workers.

The motive was understandable, but that was still a lie, and it seriously damaged public trust. It is far better to be as realistic — and candid — as possible from the start. Let’s hope this new realism continues even as some try to shame it out of existence.