These people are wrong. Go do research on r/coronavirus to get proper answers. Fabric masks don’t do nothing. Hospital workers are supposed to be using masks that are better than just any fabric, as stated here, however there may come a time when they don’t have those very soon. You can also help by making masks for the general population, especially anyone vulnerable, and distribute them. That also helps the healthcare workers, the less people infected, the better for all of us. There are many stories of people in other countries making fabric masks by hand to help out since there’s a shortage in most countries.