Dagan McDowell of Fox belittled a double mask mandate. She sneered and basically said if one mask doesn't work; why would 2?
It is called science. A layered cloth or paper mask provides an effective barrier for respiratory droplets that can carry the virus that causes covid-19. More layers are better, hence double masking.
Ordinary cloth or paper masks have limited value as protection, because they don't block the airborne virus. However, they still reduce the risk of contracting covid from inhaling respiratory droplets. Also, they are thought to be effective at preventing the spread of the virus by infected people, before it can become airborne.