There are people who see stupid ideas (which are certainly made for all the wrong reasons), then they try to "imagine" possible ways in which it might be "useful".
Prohibiting masks would lead to the spread of disease. It's that simple. There are people who have a greater concern for their own health. There are even countries where it's not unusual for someone to wear a mask when they get sick.
And frankly, maybe people should consider wearing masks more, even when there isn't a pandemic.