Mass screening of healthy people will result in ... But you don't know they're healthy. They might be sick but (so far) asymptomatic. That's why you screen, if

Mass screening of healthy people will result in ... But you don't know they're healthy. They might be sick but (so far) asymptomatic. That's why you screen, if you have a sufficiently accurate test available and you can make a useful intervention if the test gives a positive result. If we applied your argument consistently, we would abolish all cancer screening programmes, resulting in many extra deaths because early detection and treatment didn't happen. We'd stop checking up on heart health as people age, resulting in many extra deaths because people continued to live unhealthy lifestyles without realising what it was doing to them. We wouldn't be using rapid testing for COVID-19 to detect and isolate probable asymptomatic carriers who might spread the virus to others who wouldn't be so lucky. The list goes on. Good screening programmes save lives. It's as simple as that.